LETI Climate Emergency
Design Guide
How new buildings
can meet UK
climate change
targets
2020
2021
2022
2024
2023
2030
2025
100% of all
designed new
buildings to be
zero carbon
Path to zero carbon
L ONDON
E NERGY
T RANSFORMATION
I NITIATIVE
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With thanks to all who contributed to this guide:
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Alina Congreve
Amber Fahey
Amber James
Andy Stanton
Anna Woodeson
Anthony Thornton
Ben Hopkins
Bertie Dixon
Carolina Caneva
Charlotte Booth
Charlotte Millbank
Chris Twinn
Clara B George
Clare Murray
Colin Beattie
Dan Wright
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Erica Russell
Federico Seguro
Fraser Tooth
Gabriella Seminara
Georgios Askounis
Grace Van Der Zwart
Helen Hough
Helen Newman
Hugh Dugdale
Idil Alcinkaya
Isabelle Smith
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Louise Hamot
Lucy Townsend
Martha Baulcombe
Martin Bull
Megan VanDessel
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Rossella Perniola
Rowan Riley
Sabrina Friedl
Samantha Crichton
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Georgie Rose
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Judit Kimpian
Sally Godber
Sam Botterill
Simon Mitchell
Zack Gill
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About LETI
The London Energy Transformation Initiative (LETI)
the Greater London Authority (GLA) and London
was established in 2017 to support the transition of
boroughs. LETI was established for these groups to
the capital’s built environment to net zero carbon,
work collaboratively to put together evidence-based
providing guidance that can be applied to the rest of
recommendations for two pieces of policy – the new
the United Kingdom (UK).
London Environment Strategy and the rewrite of the
London Plan (planning policy guidance published by
We do this by:
the GLA). Many of the recommendations that LETI put
→→ Engaging with stakeholders to develop a robust
forward to the GLA have been included in emerging
and rapid energy reduction approach, producing
London policy and Energy Assessment Guidance.
effective solutions to the energy trilemma of
security, sustainability, and affordability;
→→ Working
with
local
authorities
to
Over the last year LETI has focused on providing this
create
guidance on defining what good looks like in the
practicable policy alterations to ensure the
context of the climate emergency for new buildings.
regulatory system is fit for purpose, placing
This report is the culmination of these efforts. These
verified performance at its core;
ideas will inevitably refine and evolve over time.
→→ Encouraging and enabling collaboration within a large, diverse group of built environment
For more information on LETI, please see:
professionals; and
www.LETI.london
→→ Providing technical advice to support exemplar
developments, enabling leader who want to
deliver net zero carbon buildings.
LETI is a network of over 1,000
built environment
professionals who are working together to put London
on the path to a zero carbon future. The voluntary
group is made up of dedicated and passionate
developers,
engineers,
housing
association
professionals,
architects,
planners,
academics,
sustainability professionals, contractors, and facilities
managers, with support and input provided by
L ON DON
E N E RGY
T R AN SFORM ATI ON
I N ITIATIVE
Climate Emergency Design Guide
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Foreword
Leading scientists now say
that unless we change course
drastically, within the lifetime
of people alive today, we are
heading for a world which can
support only 0.5 to 1 billion
people. Such is the climate and
ecological emergency.
The warnings could not be more serious. We need all
our cities and communities, let alone buildings, to be
zero carbon without delay.
To write this report, industry experts, have come
together under Clara’s leadership to produce essential
guidance for how to design and build zero carbon
buildings. It is particularly inspiring to see so many
young professionals contributing to the report. It has
clear recommendations on design and management
processes and technologies to ensure buildings can
contribute to a zero carbon future – both operational
carbon released from use of the buildings as well
As well as guidance, this report provides exceptionally
good material to inform policy. What makes good
guidance does not necessarily make good policy. Over
the next few months we should translate the thinking
behind this guidance into policy recommendations to
get the new decade off to a good start. We will do
well to learn from what worked and what didn’t work
in the ill-fated Zero Carbon Homes policy introduced
and abandoned in the last decade. To be effective in
policy terms, zero carbon buildings must be seen and
deployed in the context of zero carbon energy policy
and zero carbon transport policy.
Without these,
it will be hard to deliver at scale on the aspirations
contained in this report. We need to ensure that the
right system is being tackled to deliver the carbon
savings effectively and cost-effectively and not the
whole burden falling on new buildings, particularly
new homes.
The time has come to get sustainability done. This
report provides an important roadmap for buildings.
Please read it. Absorb it contents. Learn from it. Build
your understanding and apply it sensibly, responding
to the unique needs of your building and the context
which contains it.
as the carbon embodied in construction. A huge
amount has been learned over the past twenty and
more years on how to design, build and operate zero
carbon buildings. So much of that learning in distilled
in this report. The guidance is a snapshot of what good
looks like today. It will need to evolve over time as we
learn more, as new technology emerges and contexts
change. Perhaps we should aim to update it at least
every five years.
LETI
Pooran Desai OBE Hon FRIBA
CEO Oneplanet.com
Co-founder, Bioregional
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Climate Emergency Design Guide
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Contents
LETI
08
Executive summary
13
Chapter 0 - Introduction
14
0.0 - Introduction
14
0.1 - Scope of this document
16
0.2 - The elements of whole life carbon
20
0.3 - Chapter guide
21
0.4 - Capacity building
22
0.5 - Zero carbon trajectory
24
0.6 - Key definitions
25
0.7 - Building archetypes
25
0.8 - Actions by RIBA Stage
35
Chapter 1: Operational energy
53
Chapter 2: Embodied carbon
67
Chapter 3: Future of heat
81
Chapter 4: Demand response and energy storage
95
Chapter 5: Data disclosure
111
Appendices
112
Appendix 0 - Net zero operational carbon and actions by RIBA Stage
118
Appendix 1 - Operational energy
128
Appendix 2 - Embodied carbon
136
Appendix 3 - Future of heat
142
Appendix 4 - Demand response and energy storage
148
Appendix 5 - Data disclosure
150
Appendix 6 - Definitions
155
Appendix 7 - Abbreviations
156
Appendix 8 - Acknowledgements
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Executive summary
The climate emergency - a call to
action
We are in a climate emergency, and urgently need
For this document net zero carbon means whole life
carbon. Whole life carbon is formed of two key
components:
to reduce carbon emissions. Here in the UK, 49% of
annual carbon emissions are attributable to buildings.
Operational Carbon: a new building with
Over the next 40 years, the world is expected to
net zero operational carbon does not burn
build 230 billion square metres of new construction1
fossil fuels, is 100% powered by renewable
– adding the equivalent of Paris to the planet every
energy, and achieves a level of energy
single week – so we must act now to meet the
performance in-use in line with our national
challenge of building net zero developments.
climate change targets.
LETI, along with others such as the World Green
Embodied Carbon: Best Practice targets for
Building Council and Architecture 2030, believe that
embodied carbon are met, and the building
in order to meet our climate change targets all new
is made from re-used materials and can be
buildings must operate at net zero carbon by 2030
disassembled at its end of life in accordance
and all buildings must operate at net zero carbon by
with the circular economy principles.
2050. This document provides practical solutions to set
out a definitive journey, beyond climate emergency
declarations, into a net zero future. To this end, the
solution to meeting our climate change targets must
be:
→→ Scalable: Energy consumption targets are set so
that there is enough renewable energy to power
all buildings in the UK.
→→ Achievable: A comprehensive modelling study
The built environment industry, together with current
regulations and practices, are seriously lagging
behind the carbon trajectory required to protect life
on planet earth. Everyone’s future is at stake. As an
industry we must be absolutely confident that all new
buildings can operate at net zero carbon from 2030.
has been undertaken, and in-use data from
buildings have been analysed, so that the
Embodied Carbon : The carbon emissions emitted
targets, while ambitious to achieve, are deemed
producing a building’s materials, their transport and
achievable for most projects.
installation on site as well as their disposal at end of life.
→→ Verifiable: Targets are measured in-use.
→→ Whole Life: Embodied carbon and operational
carbon must both be considered.
Products
Transport
Construction
Maintenance and
replacement
End of life disposal
1 - UN Global Status Report 2017
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In order to achieve this, LETI
believes that by 2025, 100 percent
of new buildings must be designed
to deliver net zero carbon, and
the whole construction industry
will need to be equipped with the
knowledge and skills necessary.
for lesson learning, knowledge transfer, and market
uptake – but only if we all act now.
This document represent LETI’s understanding of how
we need to be designing to meet our climate change
targets in 2020. This guide will evolve over time
reflecting change in carbon budgets, technologies
and capability of industry. LETI is collaborative by
nature and is very interested in your feedback, go to
the LETI website to find a general feedback form on
the design guide, with specific questions on embodied
carbon and demand response.
To set us on this trajectory, LETI believes that in 2020, 10
percent of all new buildings need to be designed to
For more information on LETI, please see:
deliver net zero carbon (see Figure i). This allows time
www.LETI.london
10% of all designed new
buildings are
2020
zero carbon
20% by
2021
2020
40% by
2022
60% by
2023
80% by
2024
2030
2025
Figure i - LETI – Getting to Zero
100% of all designed new
buildings are zero carbon
100% of all built
new buildings
are zero carbon
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We all have a role to play
Structure of this report
Every stakeholder working in the built environment
The guidance in the document outlines how we should
has a part to play, and all must work together, with the
be designing buildings now, from 2020. Buildings that
same collective ambition, for net zero carbon to be
currently meet these requirements in-use will be seen
delivered at scale.
as leaders. By 2030 these requirements must become
standard practice.
The most aspirational designer can be limited by a
client with a narrow strategic vision, and the most
The
aspirational client can be limited by design teams
magnitude of the challenges that this industry faces,
introduction
outlines
in
further
detail
the
unskilled in delivering net zero carbon. Regulation
as well as the approach taken by LETI to establish this
and policy must be implemented quickly so that the
guidance. Actions that must be taken at each RIBA
minimum standards are set to deliver net zero carbon.
design stage have been summarised in Appendix 0.
This document is intended to help the industry
Our methodology includes setting the requirements of
understand and deliver new buildings that are net zero
four key building archetypes (small scale residential,
carbon. It is specifically aimed towards developers/
medium/large scale residential, commercial offices,
landowners, designers, policy makers, and the supply
and schools).
chain. It aims to help to define ‘good’ and to set clear
Five chapters follow the introduction, delving into
and achievable targets.
details on delivery and implementable solutions
This document seeks to:
(Figure ii). Each chapter forms a key component of
→→ Aid clients and developers in setting briefs and
the journey towards a zero carbon future.
strategies both at organisational and project
levels, which are required to develop net zero
carbon buildings.
→→ Support design teams with easy-to-follow best
practice guidance on delivering net zero.
→→ Outline to planners, policymakers, local and
central government what to expect for the
delivery
and
hence
the
policy
framework
needed for net zero carbon new buildings.
Climate Emergency Design Guide
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Elements of net zero carbon
Operational energy
Embodied carbon
Future of heat
Demand response
Data disclosure
Figure ii - Elements of net zero carbon
LETI
Climate Emergency Design Guide
LETI
0
Introduction
13
0
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0.0 Introduction
0.1 Scope of this document
We are in a climate crisis and the construction industry
LETI has taken the strategic decision to focus this
is responsible for 49% of carbon emissions in the UK
report on new buildings. We acknowledge that a
(see Figure 0.1). Therefore we must take rapid action
significant portion of the built environment in 2050
to decarbonise the building industry.
(c. 80 percent) already exists and will need an equal
amount of attention by the industry, in order to fulfil
In order to limit climate change, the UK government
our responsibility towards the climate emergency.
is committed to achieving net zero emissions by 2050.
LETI along with other organisations believe that this
The focus on new buildings has been prioritised as it
is not sufficient. Global warming is predicted to be
is crucial that all new buildings are developed to a
limited to 1.5ºC only if drastic changes are made,
standard that meets our climate change targets. If
Figure 0.2 shows the magnitude of the change
not, the new buildings will just compound the problem,
needed to reach net zero carbon.
and ultimately add to the number existing buildings
requiring deep retrofit to meet our climate change
Total UK greenhouse gas emissions
31% - Transport
27% -
22% -
20% -
Business
Domestic
Other
5% - From heating
15% - From
and hot water
heating and hot
water
Figure 0.1 - The UK’s carbon footprint
Source: Information in figure 0-01 has been developed from a variety of sources. 1. National Statistics, Annex: 1990-2017 UK Greenhouse
Gas Emissions, Final Figures by End User, Issued 28/03/19. 2. Committee on Climate Change, UK housing: Fit for the future? February 2019. 3.
Committee on Climate Change, Reducing UK Emissions - 2019 Progress Report to Parliament. 4. Environmental Change Institute, 40% House,
2005
Climate Emergency Design Guide
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targets. New buildings also offer the opportunity to
Due to the rapidly evolving nature of emerging
test techniques and systems that can then be applied
knowledge in this field, this document should be read
to the existing building stock.
in conjunction with the latest guidance and technical
toolkits available, including (but not limited to) those
It is important to note that this document focuses
from the UKGBC, RICS, CIBSE, and the RIBA. We hope
on requirements and solutions related to carbon
this document offers easy-to-follow guidance for
emissions. Other aspects such as overheating, air
designers and urban planners to better understand
quality, and wellbeing are also seen as important and
how to reduce whole life carbon in the design and
must be taken into consideration when designing a
construction of buildings.
building - but are beyond the scope of this document.
CO2 emissions decline from 2020 to reach
netdecline
zero in 2040
CO2 emissions
from 2020 to
reach net zero in 2040
Business as usual
trajectory
Business as usual
trajectory
Transition to net
zero
40
30
20
10
1980
2020
2060
2100
2000
1000
0
Figure 0.2 - Magnitude of global carbon emission reductions required to limiting
warming to 1.5ºC. Intergovernmental Panel on Climate Change.
LETI
Transition to net
zero
3000
50
Carbon emissions (GtCO2/yr)
Carbon emissions (GtCO2/yr)
60
0
Cumulative CO2 emissions reaching net
zero
in2 2040
Cumulative
CO
emissions
reaching net zero in 2040
1980
2020
2060
2100
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0.2 The elements of whole
life carbon
Net zero carbon needs to be considered in the context
of whole life carbon. Whole life carbon includes
operational and embodied carbon, and these need
to be understood, and considered, very differently.
Operational - zero carbon balance
A new building with net zero operational carbon does
not burn fossil fuels, is 100% powered by renewable
energy, and achieves a level of energy performance
in-use in line with our national climate change targets.
Operational energy
This means that an operational carbon balance
is met, see Figure 0.3. LETI has carried out extensive
consultation on the key requirements for net zero
operational carbon for new buildings. No carbon
offsets can be used to achieve this balance.
SIGNPOST Appendix 0 - Net zero operational
carbon
On-site
Investment in offrenewables site renewables
Net zero operational balance
Operational energy
On-site
Investment in offFigure 0.3 - Net zero operational balance
- at the building
scale
renewables
site renewables
Net zero operational balance
For some building types, such as small scale residential,
100 % of the energy consumption can be met on-site
with roof mounted PV panels. Taller buildings have a
smaller proportion of roof area to floor area, therefore
investment in ‘additional’ renewable energy off-site
will be required. Such investment into additional
renewable energy capacity is not considered an
offset.
As well as achieving the ‘zero carbon balance’ at
a building level, it is important that this balance is
also achieved at a national level (see Figure 0.4). To
No EUI targets:
EUI targets:
renewable
energy
> energy
consumption production
renewable
energy
= energy
consumption production
meet the UK’s climate change targets all buildings
must achieve net zero operational carbon. Because
the amount of renewables that the UK can produce
is limited, to achieve operational net zero carbon at
scale in the UK, developments must not exceed an
‘energy budget’. This is set as an Energy Use Intensity
(EUI) target (see section 0.6 Key definitions).
Climate Emergency Design Guide
No EUI targets:
EUI targets:
renewable
energy
> energy
consumption production
renewable
energy
= energy
consumption production
Figure 0.4 - Net zero operational balance - at UK scale
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Embodied carbon
Whole life net zero carbon
Operational carbon is based on the flow of energy
One school of thought is that offsetting can be used
and needs to be generated through renewables.
to achieve net zero embodied carbon. However,
Constructing buildings uses energy as well as
offsets are a controversial subject, with significant
resources, and once a building has come to the end
issues related to transparency and effectiveness.
of its life, these resources are still potentially available
This guidance document does not expand on offsets
for use. Thus in addition to reducing embodied carbon
as this bears no relation to the performance of a
we must consider the resources as a ‘store’ rather
building. LETI have taken a view that circularity is
than a ‘flow’ and buildings should be thought of as
more relevant than offsets for the design team and
‘material resource banks’.
for policy makers. However, as offsets can be seen as
means to reduce the residual emissions of embodied
The
embodied
carbon
emissions
need
to
be
considered within national and regional carbon
budgeting. This means that the carbon emissions
themselves need to be reduced which is why LETI
has set embodied carbon targets for the upfront
embodied carbon emissions (Building Life Cycle
Stage A1-A5). In addition, the material resources used
need to be kept in the circular economy. This means
that the building re-uses materials and products from
demolished buildings, and is designed for disassembly,
so that materials and products within the building can
be re-used in future buildings.
LETI defines whole life carbon best practice as a
building that meets the operational zero carbon
balance, and that meets best practice targets for
embodied carbon, including upfront embodied
carbon targets, proportion of materials that are from
re-used sources and proportion of materials that can
be re-used in future buildings.
LETI
carbon Appendix 10 of the Embodied Carbon Primer
gives a dispassionate review of offsetting, looking at
the advantages, disadvantages and technical and
societal challenges to its effective implementation.
A building that is whole life net zero carbon meets
the operational zero carbon balance and is 100%
circular, this means that 100% of its materials and
products are made up of re-used materials and
the building is designed for disassembly such that
100% of its materials and products can be re-used in
future buildings. When construction, transport and
disassembly is carried out with renewable energy
there will be zero carbon emissions associated with
the embodied carbon.
SIGNPOST Embodied Carbon Primer - Appendix
10 - Carbon offsets
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Whole life carbon explained
Whole life carbon encompasses all carbon emissions
that arise as a result of the energy used in the
construction, operation, maintenance and demolition
phases of a building.
Figure 0.5 shows the operational carbon reduction
stages on the left, and the embodied carbon
BUILDING REGULATION
COMPLIANT BUILDING
NET ZERO OPERATIONAL
CARBON
reduction stages on the right.
Operational energy
→
→
Meet EUI target
Meet heating
demand target
Future of heat
→
Use low
carbon heat
EUI = Energy use intensity (kWh/m2.yr)
Operational carbon
Embodied carbon
Climate Emergency Design Guide
Demand response
→
Incorporate
demand
response
measures
Renewables
→
Incorporate
renewable
energy
on-site
Data disclosure
→
→
Monitor energy use
Any energy not
met by on-site
renewables
must be met by
an investment
into additional
renewable
capacity
0
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Whole life carbon
= Operational carbon + Embodied carbon
zero
Best Practice targets for embodied
operational carbon does not burn fossil
new
building
that
meets
net
carbon are met, the building is made
fuels, is 100% powered by renewable
from re-used materials and can be
energy, and achieves a level of energy
disassembled at end of its life - in
performance in-use in line with our national
accordance with the circular economy
climate change targets. See Appendix 0.
principles.
SIGNPOST
SIGNPOST
Chapters 1,3,4
and 5 cover
operational
carbon
Chapter 2 and the
Embodied Carbon Primer
cover embodied carbon
CURRENT BUILDINGS
CIRCULAR ECONOMY
WHOLE LIFE CARBON
A
Embodied carbon
Made from
re-used
materials
→
→
→
→
→
Upfront embodied target
Circular economy
Design for
disassembly
Operational energy balance
→
Whole life carbon
Reduce
embodied
carbon
Figure 0.5 - Whole life carbon
LETI
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0.3 Chapter guide
Operational energy
Future of heat
Operational energy is the energy consumed
The decarbonisation of heating and hot
by a building associated with heating, hot
water will have a huge impact on carbon
water, cooling, ventilation, and lighting systems, as well
emission reductions and is a crucial step in the net
as equipment such as fridges, washing machines, TVs,
zero pathway. Chapter 3 showcases the LETI Heat
computers, lifts, and cooking. Reducing operational
Decision Tree, a tool that can be used to help identify
energy is key to achieving scalable zero carbon. The
the most appropriate low carbon heating system.
archetype summary pages outline performance
requirements and Chapter 1 provides guidance on
SIGNPOST Chapter 3 - Future of heat
the key levers that drive operational performance.
SIGNPOST Chapter 1 - Operational energy
Embodied carbon
Demand response
Integrating demand response and energy
storage into buildings allows buildings to be
The term embodied carbon refers to the
flexible with their demand on the grid for power. This
‘upfront’ emissions associated with building
is fundamental to allow the grid to harness renewable
construction, including the extraction and processing
energy sources that allows it to decarbonise to a level
of materials and the energy and water consumption
in the production, assembly, and construction of
the building. It also includes the ‘in-use’ stage (the
maintenance, replacement, and emissions associated
with refrigerant leakage) and the ‘end of life’ stage
that is needed to meet our climate change targets.
Chapter 4 outlines key actions that can be taken to
improve a building’s power flexibility.
SIGNPOST Chapter 4 - Demand response
(demolition, disassembly, and disposal of any parts of
product or building) and any transportation relating
to the above. Embodied carbon is a topic that is
becoming more relevant and important as we reduce
operational carbon.
Currently there is a lack of knowledge in the built
environment industry surrounding embodied carbon
reduction strategies and calculations, and the
verification of the installed materials. Therefore LETI
has produced supplementary guidance in the form of
the LETI Embodied Carbon Primer. The key messages
from the primer are summarised in Chapter 2 of this
report.
SIGNPOST Chapter 2 - Embodied carbon
SIGNPOST Embodied Carbon Primer
Climate Emergency Design Guide
Data disclosure
Unless we can gain a good understanding
of how our buildings are performing in-use
through post occupancy evaluation, we cannot
achieve net zero carbon. Currently the way that
buildings are assessed in regulations is
according
to a Building Regulations energy model (Part L)
rather than in-use consumption. There is also a huge
‘performance gap’ between how we estimate the
energy consumption of new buildings and how they
perform in-use. Chapter 5 outlines the steps we need
to take to start understanding how our buildings are
performing in-use by better measuring and monitoring
energy consumption.
SIGNPOST Chapter 5 - Data disclosure
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0.4 Capacity building
As well as design teams focusing on the 5 key
Constructing: Contractors need to learn how to
themes, regulations and policy will also be needed to
construct buildings that achieve high levels of
incentivise and mandate net zero carbon.
airtightness and insulation and effectively reduce/
eliminate the effects of thermal bridging. The full
Significant leaps will need to be made upskilling and
implications of specification substitution must be
capacity building, to ensure that the built environment
clearly defined.
industry has the skills to deliver net zero buildings. This
document has been developed as a first step towards
Operating and facilities management: The role of
this.
the facilities manager in reducing carbon emissions
needs to be properly recognised. Performance
Upskilling will be required in the following areas:
outcomes need to be based on energy consumption.
On a smaller scale, users need to be made aware of
Energy Modelling: To ensure the correct motivation
drives energy modelling, there must be a legal
responsibility to ensure it is directly reconciled against
in-use measured energy use. So rather than just
compliance modelling, the UK needs to upskill in
predictive modelling. This means that design decisions
such as fabric performance and system selection
can be based on predictions of energy consumption
reduction. Demand response measures that increase
the ‘energy flexibility’ of the development can also be
assessed.
Designing:
The
whole
design
team
needs
to
understand their individual contributions towards
reductions of operational energy and embodied
carbon in a cost-effective way. A ‘golden thread’ of
responsibility from design through construction and
into operation will be needed to ensure decisions are
implemented and their operation verified.
LETI
how to operate their building in a low carbon way.
0
22
0.5 Zero carbon trajectory
2020
The following graphic illustrates the key milestones
that must be achieved in order to ensure that the UK
will have a zero carbon built environment by 2050.
2025-2030
Improved cost-effectiveness by
industry upskilling.
Operational energy
All new buildings designed to be
Data disclosure
All buildings (new and existing) to
disclose energy use data.
Demand response
Policy to mandate minimum
requirements for metrics.
net zero operational carbon.
Operational energy
All new buildings to operate at net zero
operational carbon.
2030
Embodied carbon
All new buildings achieve a 65% reduction in
embodied carbon emissions.
2025
0
23
2020-2025
Five years to design
and build pathfinders;
working out what to
do with existing stock.
Operational energy
UK building regulations
must be updated to clearly
signpost how and when it
will transition to mandatory
verification of in-use energy
consumption. Building
industry to adopt Energy
Use Intensity (EUI) targets.
Embodied carbon
All buildings to conduct whole life
carbon calculations and aim to achieve
40% carbon emission reductions.
Future of heat
All new buildings are fossil fuel free.
Data disclosure
All new buildings to disclose energy use
data.
Operational energy
Introduction of regulatory performance
framework with EUI requirements.
Embodied carbon
Benchmarks and methodology to be
established and regulation introduced
to ensure benchmarks are met.
2050
2022
Demand response
Metrics around
demand response to be
established.
2025-2050
Upgrade to zero carbon at a rate of
3,750 homes per day! Upgrade existing
non-domestic buildings.
Figure 0.6 - Zero carbon trajectory
0
24
0.6 Key definitions
Key definitions and abbreviations used in this guide:
Regulated energy: Energy consumed by a building,
associated with fixed installations for heating, hot
What is an EUI?
The Energy Use Intensity (EUI) is an annual measure
of the total energy consumed in a building.
water, cooling, ventilation, and lighting systems.
Unregulated energy: Energy consumed by a building
that is outside of the scope of Building Regulations,
LETI believes that setting an EUI requirement for new
e.g. energy associated with equipment such as
buildings is fundamental to meeting our climate
fridges, washing machines, TVs, computers, lifts, and
change targets. It is a good indicator for building
cooking.
performance as the metric is solely dependent
on how the building performs in-use; rather than
Operational carbon (kgCO2e): The carbon dioxide
carbon emissions, which also reflect the carbon
and equivalent global warming potential (GWP) of
intensity of the grid.
other gases associated with the in-use operation of
the building. This usually includes carbon emissions
EUI is a metric that can be estimated at the
associated
design stage and very easily monitored in-use as
ventilation, and lighting systems, as well as those
energy bills are based on kWh of energy used by
associated with cooking, equipment, and lifts (i.e.
the building. This metric can be used to compare
both regulated and unregulated energy uses).
buildings of a similar type, to understand how
with
heating,
hot
water,
cooling,
well the building performs in-use. It includes all
Embodied
energy:
of the energy consumed in the building, such as
consumed
(e.g. in MJ) from direct and indirect
regulated energy (heating, hot water, cooling,
processes associated with the production of a product
ventilation, and lighting) and unregulated energy
or system. This is considered within the boundaries of
(plug loads and equipment e.g. kitchen white
cradle-to-gate.
goods, ICT/AV equipment). It does not include
charging of electric vehicles.
The
Upfront embodied carbon:
total
primary
energy
The carbon emissions
associated with the extraction and processing of
EUI can be expressed in GIA (Gross Internal Area)
materials, the energy and water consumption used
or NLA (Net Lettable Area). In this document the
by the factory in producing products, transporting
EUIs are expressed in GIA unless specified.
materials to site, and constructing the building.
EUI should replace carbon emission reductions as
Embodied
the primary metric used in policy, regulations, and
associated with the extraction and processing of
design decisions.
materials and the energy and water consumption
carbon
(EC):
The
carbon
emissions
used by the factory in producing products and
constructing the building. It also includes the ‘in-use’
stage (maintenance, replacement, and emissions
Climate Emergency Design Guide
0
25
0.7 Building archetypes
associated with refrigerant leakage) and ‘end of life’
This guide focuses on four building archetypes that
stage (demolition, disassembly, and disposal of any
make up the majority of new buildings in the UK. Taken
parts of product or building) and any transportation
together they represent 75% of the new buildings likely
relating to the above.
to be built between now and 2050.
Whole life carbon (WLC): This includes embodied
Archetypes detailed in this report:
carbon, as defined above, and operational carbon.
→→ Small
The purpose of using WLC is to move towards a
building or a product that generates the lowest
carbon emissions over its whole life (sometimes
referred as ‘cradle-to-grave’).
scale
residential:
terraced
or
semi-
detached houses
→→ Medium and large scale residential: four floors
and above
→→ Commercial offices
→→ Schools: Primary or secondary
Primary energy: Primary energy is energy that has not
undergone any conversion or transformation. As a
The following pages show the key performance
common example, each kWh of grid electricity used
indicators to meet whole life carbon for the four
in a UK building requires 1.5 kWh of primary energy;
building typologies.
this accounts for the energy required for power
generation (including fuel extraction and transport to
thermal or nuclear power stations), transmission and
distribution.
Circular economy: A circular economy is an industrial
system that is restorative or regenerative by intention
and design. It replaces the linear economy and its
‘end of life’ concept with restoration, shifts towards
the use of renewable energy, eliminates the use of
toxic chemicals and aims for the elimination of waste
through the design of materials, products, systems
that can be repaired and reused.
SIGNPOST Appendix 6 - Definitions
LETI
0.8 Actions by RIBA Stage
Appendix 0.2 shows the actions required to meet
net zero carbon for each RIBA Stages. This helps
understand which actions need to be taken at each
stage to ensure whole life carbon is achieved.
SIGNPOST Appendix 0 - Actions by RIBA Stage
0
26
Small scale housing
Operational energy
Implement the following indicative design measures:
Fabric U-values (W/m2.K)
Walls
0.13 - 0.15
Floor
0.08 - 0.10
Roof
0.10 - 0.12
Exposed ceilings/floors 0.13 - 0.18
Windows
0.80 (triple glazing)
Doors
1.00
Efficiency measures
Air tightness
Thermal bridging
G-value of glass
MVHR
Window areas guide
(% of wall area)
North 10-15%
East
10-15%
South 20-25%
West
10-15%
Reduce energy consumption to:
35
kWh/m2.yr
Balance
daylight and
overheating
<1 (m3/h. m2@50Pa)
0.04 (y-value)
0.6 - 0.5
Include external
shading
Reduce space
heating
demand to:
Energy Use
Intensity
(EUI) in GIA,
excluding
renewable
energy
contribution
15
kWh/m2.yr
Include openable
windows and
cross ventilation
90% (efficiency)
≤2m (duct length
from unit to
external wall)
Maximise
renewables so that
100% of annual
energy requirement
is generated on-site
Form factor of 1.7
- 2.5
Embodied carbon
Focus on reducing embodied carbon
for the largest uses:
Products/materials (A1-A3)
Small resi
<1%
Med/high resi
<1%
14%
30% - Superstructure
Transport (A4)
Construction (A5)
Average split of embodied carbon
per building element:
80%
5%
27% - Substructure
20% - Internal finishes
Maintenance and
replacements (B1-B5)
17% - Façade
End of life disposal (C1-C4)
Reduce
embodied
carbon by
40% or to:
<500
kgCO2/m2
5% - MEP
OFFICE
Area in GIA
0
27
Heating and hot water
Demand response
Implement the following measures:
Implement the following measures to smooth energy
demand and consumption:
Fuel
Ensure heating and hot water generation is
fossil fuel free
Peak reduction
Reduce heating and hot water peak
energy demand
Heating
Maximum 10 W/m2 peak heat loss (including
ventilation)
Active demand response measures
Install heating set point control and
thermal storage
Hot water
Maximum dead leg of 1 litre for hot water
pipework
Electricity generation and storage
Consider battery storage
'Green' Euro Water Label should be used
for hot water outlets (e.g.: certified 6 L/min
shower head – not using flow restrictors).
Electric vehicle (EV) charging
Electric vehicle turn down
Behaviour change
Incentives to reduce power consumption
and peak grid constraints.
Data disclosure
Meter and disclose energy consumption as follows:
123
Metering
1.
Submeter renewables for energy generation
2.
Submeter electric vehicle charging
3.
Submeter heating fuel (e.g. heat pump
consumption)
4.
Continuously monitor with a smart meter
5.
Consider monitoring internal temperatures
6.
For multiple properties include a data logger
alongside the smart meter to make data
sharing possible.
Disclosure
1.
Collect annual building energy consumption
and generation
2.
Aggregate average operational reporting
e.g. by post code for anonymity or upstream
meters
3.
Collect water consumption meter readings
4.
Upload five years of data to GLA and/or
CarbonBuzz online platform
5.
Consider uploading to Low Energy Building
Database.
0
28
Medium and large scale housing
Operational energy
Implement the following indicative design measures:
Fabric U-values (W/m2.K)
Walls
0.13 - 0.15
Floor
0.08 - 0.10
Roof
0.10 - 0.12
Exposed ceilings/floors 0.13 - 0.18
Windows
1.0 (triple glazing)
Doors
1.00
Efficiency measures
Air tightness
Thermal bridging
G-value of glass
MVHR
Window areas guide
(% of wall area)
North 10-20%
East
10-15%
South 20-25%
West
10-15%
Reduce energy consumption to:
35
kWh/m2.yr
Balance
daylight and
overheating
<1 (m3/h.m2@50Pa)
0.04 (y-value)
0.6 - 0.5
Include external
shading
Reduce space
heating
demand to:
Energy Use
Intensity
(EUI) in GIA,
excluding
renewable
energy
contribution
15
kWh/m2.yr
Include openable
windows and
cross ventilation
90% (efficiency)
≤2m (duct length
from unit to
external wall)
Maximise
renewables so that
70% of the roof is
covered
Form factor of <0.8
- 1.5
Embodied carbon
Focus on reducing embodied carbon
Smalluses:
resi
for the largest
Med/high resi
1%
Products/materials (A1-A3)
Average split of embodied carbon
per building element:
25%
46% - Superstructure
Transport (A4)
Construction (A5)
21% - Substructure
64%
2%
Maintenance and
replacements (B1-B5)
End of life disposal (C1-C4)
OFFICE
16% - Internal finishes
13% - Façade
8%
Reduce
embodied
carbon by
40% or to:
<500
kgCO2/m2
4% - MEP
Area in GIA
0
29
Heating and hot water
Demand response
Implement the following measures:
Implement the following measures to smooth energy
demand and consumption:
Fuel
Ensure heating and hot water generation is
fossil fuel free
Peak reduction
Reduce heating and hot water peak
energy demand
Heat
The average carbon content of heat supplied
(gCO2/kWh.yr) should be reported in-use
Active demand response measures
Install heating set point control and
thermal storage
Heating
Maximum 10 W/m2 peak heat loss (including
ventilation)
Electricity generation and storage
Consider battery storage
Hot water
Maximum dead leg of 1 litre for hot water
pipework
Electric vehicle (EV) charging
Electric vehicle turn down
'Green' Euro Water Label should be used
for hot water outlets (e.g.: certified 6 L/min
shower head – not using flow restrictors).
Behaviour change
Incentives to reduce power consumption
and peak grid constraints.
Data disclosure
Meter and disclose energy consumption as follows:
123
Metering
1.
Submeter renewables for energy generation
2.
Submeter electric vehicle charging
3.
Submeter heating fuel (e.g. heat pump
consumption)
4.
Continuously monitor with a smart meter
5.
Consider monitoring internal temperatures
6.
For multiple properties include a data logger
alongside the smart meter to make data
sharing possible.
Disclosure
1.
Collect annual building energy consumption
and generation
2.
Aggregate average operational reporting
e.g. by post code for anonymity or upstream
meters from part or whole of apartment block
3.
Collect water consumption meter readings
4.
Upload five years of data to GLA and/or
CarbonBuzz online platform
5.
Consider uploading to Low Energy Building
Database.
0
30
Commercial offices
Operational energy
Implement the following indicative design measures:
Fabric U-values (W/m2.K)
Walls
0.12 - 0.15
Floor
0.10 - 0.12
Roof
0.10 - 0.12
Windows
1.0 (triple glazing) 1.2 (double glazing)
Doors
1.2
Fabric efficiency measures
Air tightness
<1 (m3/h. m2@50Pa)
Thermal bridging
0.04 (y-value)
G-value of glass
0.4 - 0.3
Window areas guide
(% of wall area)
North 25-40%
East
25-40%
South 25-40%
West
25-40%
Balance
daylight and
overheating
Maximise renewables
to generate the annual
energy requirement for
Small resi at least two floors of the
development on-site
≥ 2.8
≥ 5.5
Central AHU SFP
1.5 - 1.2 W/l.s
A/C set points
20-26oC
15
kWh/m2.yr
Med/high resi
Form factor of 1 - 2
90% (efficiency)
Chiller SEER
Reduce space
heating
demand to:
Energy Use
Intensity
(EUI) in GIA,
excluding
renewable
energy
contribution
Include openable
windows and
cross ventilation
System efficiency measures
Heat pump SCoP
55
kWh/m2.yr
Include external
shading
Power efficiency measures
Lighting power density 4.5 (W/m2 peak NIA)
Lighting out of hours
0.5 (W/m2 peak NIA)
Tenant power density
8 (W/m2 peak NIA)
ICT loads
0.5 (W/m2 peak NIA)
Small power out of hours 2 (W/m2 peak NIA)
MVHR
Reduce energy consumption to:
Embodied carbon
Focus on reducing embodied carbon
for the largest uses:
OFFICE
2%
Average split of embodied carbon
per building element:
Products/materials (A1-A3)
48% - Superstructure
Transport (A4)
45%
Construction (A5)
48%
17% - Substructure
16% - Façade
Maintenance and
replacements (B1-B5)
15% - MEP
End of life disposal (C1-C4)
2%
School
3%
Reduce
embodied
carbon by
40% or to:
<600
kgCO2/m2
4% - Internal finishes
Area in GIA
0
31
Heating and hot water
Demand response
Implement the following measures:
Implement the following measures to smooth energy
demand and consumption:
Fuel
Ensure heating and hot water generation is
fossil fuel free
Peak reduction
Reduce heating and hot water peak
energy demand
Heat
The average carbon content of heat supplied
(gCO2/kWh.yr) should be reported in-use
Active demand response measures
Install heating and cooling set point
control
Heating
Maximum 10 W/m2 peak heat loss (including
ventilation)
Reduce lighting, ventilation and small
power energy consumption
Connect to community wide ambient loop
heat-sharing network to allow excess heat
from cooling to be made available to other
buildings
Electricity generation and storage
Consider battery storage
Electric vehicle (EV) charging
Electric vehicle turn down
Reverse charging EV technology
Hot water
Maximum dead leg of 1 litre for hot water
pipework
Behaviour change
Incentives to reduce power consumption
and peak grid constraints
Encourage responsible occupancy.
'Green' Euro Water Label should be used
for hot water outlets (e.g.: certified 6 L/min
shower head – not using flow restrictors).
Data disclosure
Meter and disclose energy consumption as follows:
Metering
(Metering strategy following BBP
Better Metering Toolkit guidance)
123
Disclosure
1.
Record meter data at half hourly intervals
1.
2.
Separate landlord and tenant energy use meters
and clearly label meters with serial number and
end use
Carry out an annual Display Energy Certificate
(DEC) and include as part of annual reporting
2.
3.
Submeter renewable energy generation
Report energy consumption by fuel type
and respective benchmarks from the DEC
technical table
4.
Use a central repository for data that has a
minimum of 18 months data storage
3.
5.
Provide thorough set of meter schematics and
information on maintenance and use of meters
For multi-let commercial offices produce
annual landlord energy (base building) rating
and tenant ratings as well as or instead of a
whole building DEC
6.
Ensure metering commissioning includes
validation of manual compared to half hourly
readings.
4.
Upload five years of data to a publicly
accessible database such as GLA and/or
CarbonBuzz.
0
32
Schools
Operational energy
Implement the following indicative design measures:
Fabric U-values (W/m2.K)
Walls
0.13 - 0.15
Floor
0.09 - 0.12
Roof
0.10 - 0.12
Windows
1.0 (triple glazing)
Doors
1.2
Window areas guide
(% of wall area)
North 15-25%
East
15-25%
Small
resi
South 15-25%
West
15-25%
Balance
daylight and
overheating
Fabric efficiency measures
Air tightness
<1 (m3/h. m2@50Pa)
Thermal bridging
0.04 (y-value)
G-value of glass
0.5 - 0.4
Include external
shading
Power efficiency measures
Lighting power density 4.5 (W/m2 peak NIA)
Lighting out of hours
0.5 (W/m2 peak NIA)
Small power out of hours 2 (W/m2 peak NIA)
System efficiency measures
MVHR
90% (efficiency)
Heat pump SCoP
≥ 2.8
Central AHU SFP
1.5 - 1.2 W/l.s
Include openable
windows and
cross ventilation
Reduce energy consumption to:
65
Energy Use
Intensity
Med/high resi (EUI) in GIA,
excluding
renewable
kWh/m2.yr
energy
contribution
Reduce space
heating
demand to:
15
kWh/m2.yr
Form factor of 1 - 3
OFFICE
Maximise renewables
so that 70% of the roof is
covered
Embodied carbon
Focus on reducing embodied carbon
for the largest uses:
School
1%
Average split of embodied carbon
per building element:
Products/materials (A1-A3)
Construction (A5)
30% - Superstructure
30%
Transport (A4)
21% - Internal finishes
1%
65%
Maintenance and
replacements (B1-B5)
End of life disposal (C1-C4)
16% - Substructure
16% - Façade
3%
Reduce
embodied
carbon by
40% or to:
<600
kgCO2/m2
13% - MEP
Area in GIA
0
33
Heating and hot water
Demand response
Implement the following measures:
Implement the following measures to smooth energy
demand and consumption:
Fuel
Ensure heating and hot water generation is
fossil fuel free
Peak reduction
Reduce heating and hot water peak
energy demand
Heat
The average carbon content of heat supplied
(gCO2/kWh.yr) should be reported in-use
Active demand response measures
Install heating and cooling set point
control
Heating
Maximum 10 W/m2 peak heat loss (including
ventilation)
Reduce lighting, ventilation and small
power energy consumption
Hot water
Maximum dead leg of 1 litre for hot water
pipework
Electricity generation and storage
Consider battery storage
'Green' Euro Water Label should be used
for hot water outlets (e.g.: certified 6 L/min
shower head – not using flow restrictors).
Electric vehicle (EV) charging
Electric vehicle turn down
Reverse charging EV technology
Behaviour change
Incentives to reduce power consumption
and peak grid constraints
Encourage responsible occupancy.
Data disclosure
Meter and disclose energy consumption as follows:
Metering
(Metering strategy following BBP
Better Metering Toolkit guidance)
123
Disclosure
1.
Record meter data at half hourly intervals
1.
2.
Clearly label meters with serial number and end
use
Carry out an annual Display Energy Certificate
(DEC) and include as part of annual reporting
2.
3.
Submeter renewable energy generation
4.
Use a central repository for data that has a
minimum of 18 months data storage
Report energy consumption by fuel type
and respective benchmarks from the DEC
technical table
3.
5.
Provide thorough set of meter schematics and
information on maintenance and use of meters
Upload five years of data to a publicly
accessible database such as GLA and/or
CarbonBuzz. Include information about the
building (do not anonymise).
6.
Ensure metering commissioning includes
validation of manual compared to half hourly
readings.
Climate Emergency Design Guide
LETI
1
Operational
energy
35
1
36
Key performance
indicators
1
2
3
Design for and
achieve the
energy use
intensity (EUI)
targets:
Design for and
achieve the
space heating
demand
target:
Maximise
renewable
energy
generation
on-site:
kWh/m2.yr
35
kWh/m2.yr
55
kWh/m2.yr
Residential
Offices
Schools
Offices: Generate
the annual energy
requirement for at
least two floors of
the development
on-site
Schools: Cover 70%
of the roof area
15
kWh/m2.yr
All building types
Small scale resi: Generate
100% of annual energy
requirement on-site
Medium and large scale
resi: Cover 70% of roof area
EUI targets above are based on GIA areas and exclude renewable energy contribution.
Climate Emergency Design Guide
65
1
37
Summary
Client/developer (decision
making)
→→ Apply equal or greater weighting to building
operational performance than to aesthetic
considerations in the overall context of the design,
→→ Commit to a net zero carbon vision and disclose
pathway towards achieving this goal.
→→ Appoint key design team members to influence
operational energy performance outcomes early
in the design process.
→→ Commit to energy benchmarking exercises and
set established performance targets early in the
design process - ideally prior to commencement
of concept design (RIBA Stage 2).
→→ Ensure that life cycle cost analysis and whole life
carbon analysis are carried out for all projects,
giving both appropriate weighting in value
engineering decision making.
→→ Commit
to
disclosure
of
regulated
and
unregulated building energy consumption at
both design and operation stages.
→→ Issue briefing documents that set out targets
aligned with this guidance document.
archetypes
and
request clarification where targets are not being
met.
→→ Establish expertise within planning departments
that are capable of assessing adherence to the
key performance metrics.
→→ Establish requirements (such as Supplementary
Planning
Guidance)
that
directly
cite
recommendations set out in this document.
LETI
in design, highlighting delivery strategies for
through which net zero carbon can be delivered.
→→ Design in accordance with the recommended
key performance targets for each building
archetype.
→→ Ensure that design decisions reflect the energy
hierarchy - seek to limit building energy demand
through passive measures and efficient fabric
design prior to considering systems’ optimisation
to satisfy demand.
→→ Design to recommended heating and hot water
coefficients of performance (COP). This includes
heating, cooling, hot water and lighting demand
of both regulated and unregulated energy end
metrics prior to planning approval. Evaluate
LETI
→→ Produce net zero operation pathways for projects
→→ System design to be carried out with consideration
→→ Request disclosure of key building performance
against
Designer (implementation)
kWh/m2.yr.
Policymaker (strategy)
performance
pre-application and determination process.
the
uses.
→→ Dedicate
resources
to
staff
learning
and
development to improve familiarity with key
terminology and influence on building energy
performance. This includes understanding key
activities required within each RIBA work stage.
1
38
1.0 Introduction
3.1 Contribution to zero
carbon (why do it?)
Operational carbon refers to the carbon dioxide and
Operational carbon represents between 40% and
other greenhouse gases which are emitted as a result
65% of a building’s whole life carbon. It influences
of a building’s energy use. This typically includes
the ability to achieve a net zero built environment
emissions associated with heating, hot water, cooling,
through a number of different interdependent factors,
ventilation and lighting systems, as well as energy
detailed below.
used for cooking and by specialist equipment such
as lifts.
Operational carbon is arguably the most direct
consistent environmental impact that a building has
This is distinctly different to ‘embodied’ carbon,
throughout its life cycle and is directly related to the
which refers to the carbon emissions incurred from
ways in which we occupy and interact with buildings.
the manufacture, transport and erection of building
It is a building’s carbon legacy. In the context of the
materials used in the construction of a building (for
climate emergency, there is an urgent need to limit
detail see Chapter 2 - Embodied Carbon). Operational
these ongoing impacts.
emissions can vary over the lifetime of the building
and are governed by several factors, including
A net zero carbon building is first and foremost an
building fabric efficiency, Heating, Ventilation and
energy efficient building.
Air Conditioning (HVAC) system efficiency, fuel type,
LETI consider a building’s low energy consumption to
carbon factors and the way the building is used by
be the defining characteristic of an operational zero
the occupiers.
carbon building. Energy consumption is measured
using Energy Use Intensity (EUI) with kWh/m2.yr as a
Historically, operational emissions have far outweighed
unit. Design approaches should begin with efforts
the embodied emissions. However, as the efficiency
to reduce building energy demand prior to the
of our buildings improves and carbon factors reduce,
introduction of complex mechanical systems which
consideration of the embodied energy becomes
reduce the energy required to satisfy this demand.
increasingly important.
Only after a thorough consideration of these steps
should renewable energy generation be considered.
SIGNPOST Chapter 2 - Embodied carbon
Climate Emergency Design Guide
The lower the energy demand of the building, the
easier it is to achieve net zero in use.
1
39
Reducing energy demand of built assets reduces
stress on grid infrastructure.
Lowering or eliminating the energy demand of new
buildings will not only reduce the size and capital cost
of plant equipment, but can subsequently reduce
the cumulative stress applied to the national grid
infrastructure. This is because there is a lower peak
demand required and the load is likely to be more
flexible due to the thermal stability of the building.
Operational carbon
Practical completion
Replacement and maintenance
Operational
emissions
0
10
20
30
40
Use stage (years)
Building lifecycle
Figure 1.1 - Graph showing interaction between operational and embodied
carbon throughout the lifetime of a building
LETI
End of life
Carbon emissions (kgCO2)
Embodied carbon
50
60
1
40
1.2 Current challenges
Metrics: carbon and energy
The current UK regulatory framework within Approved
Methodology: regulated vs.
unregulated energy
Document L of the Building Regulations uses carbon
Operational energy consumption is often categorised
emissions as the basis to determine compliance. There
are a number of flaws/unintended consequences
in using this methodology, most notably the carbon
intensities of energy fuel supply adversely influencing
on-site efficiency measures, and the neglect of
building envelope efficiency in favour of mechanical
systems’ efficiencies. To address these issues, LETI
believes that the operational energy of a building is
the main metric that should be used, as this is likely to
be relatively consistent through the building’s lifetime.
Culture: design for compliance vs.
performance
into
two
key
components.
‘Regulated’
energy
consumption results from controlled, fixed building
services including heating and cooling, hot water,
ventilation
and
lighting.
‘Unregulated’
energy
consumption results from processes that are not
covered by building regulations, i.e. ICT equipment,
lifts, refrigeration systems, cooking equipment and
other ‘small power’.
One of the well documented shortcomings of the
current Part L calculation methodology is its omission
of unregulated energy loads. Although it can vary
considerably by building type, unregulated energy
can form up to 50% of total operational energy. The
The UK national standard methodology for assessing
lack of consideration of unregulated energy at a
energy compliance relies on a predefined set of
regulatory level can lead to drastically different
assumptions and was created primarily for different
consumption to that estimated at the design stage.
building design proposals to be compared to
one another. Whilst this method does form a level
playing field for design proposals to be evaluated, it
promotes a ‘design for compliance’ culture in which
a short-term objective − compliance with regulations
− is sought with little regard to how the building will
actually perform in operation. The consequences
of this approach are evident in much of our existing
building stock, with operational performing much
worse than anticipated at design. They achieve
performance in theory but not in practice. The lack of
feedback loops to communicate disparity between
design and operation is considered to be one of the
primary causes of the performance gap which is
further discussed opposite.
Regulated loads:
→→ Heating
→→ Cooling
→→ Hot water
→→ Lighting
→→ Pumps and fans
Unregulated loads are
plug loads such as:
→→ Cooking
→→ Appliances
→→ TVs
→→ Computers
→→ Any other electrical
equipment
Figure 1.2 - Regulated and unregulated energy
Climate Emergency Design Guide
1
41
Operation: the performance gap cause and effect
Industry skills gap
The performance gap is defined as the deficit
high performance design and construction in the UK
between predictions of energy consumption from
building compliance tools and actual measured
energy use during operation. This determines
whether a building and its systems work as expected
when occupied, as well as the extent of the gap
where not. Expectations for performance may be
defined by regulatory targets or client requirements.
One of the most significant barriers to adoption of
is the industry skills gap in delivering ultra-low energy
buildings. While design professionals lack proficiency
in design strategies and terminology, construction
professionals and Building Control bodies do not fully
understand their practical application. This often
results in exaggerated capital cost estimates, typically
attributed to two key aspects: achieving high levels of
airtightness on site (including testing procedures), and
additional site supervision and quality assurance.
The causes of the performance gap have been found
to be wide-ranging and complex, including many
LETI’s experience suggests that these capital cost
of the items listed above. Many of the contributory
estimates are often inflated as a precautionary
causes to the performance gap can be categorised
measure to absorb any additional time required for
into performance at three different stages: design,
construction teams to undergo necessary training
completion,
research
and any perceived risk. These cost uplifts have
carried out by the UK Passivhaus Trust determined
been found to correlate with building height due to
an average performance gap of 40% between
the increasing importance of planning for optimal
the overall energy use of a new build house when
sequencing, as well as the narrowing choice of
compared to its EPC modelling and other evidence
construction methodologies as the buildings increase
suggests that it can be up to 500%. In order to deliver
in height.
and
in-use.
Independent
a net zero built environment by 2050, it is therefore
critical that this performance gap is closed.
Further information on the performance gap is
provided in Appendix 1.2.
SIGNPOST Appendix 1 - Operational energy
LETI
1
42
1.3 Key components/
solutions (what?)
Achieving a net zero carbon built environment
occur on a national scale — it effectively establishes a
requires substantial reductions in energy demand
‘budget’ for our energy demand.
from buildings, combined with decarbonisation of the
electricity grid through an increase in the renewable
This method ensures that the recommendations for
energy contribution, as well as ensuring heat sources
achieving net zero carbon buildings not only take into
which are fossil fuel free.
account the expected national grid decarbonisation,
but also reflect current technology and best practice
LETI have taken a two-dimensional approach to
energy conservation measures. LETI’s basic premise
establishing Energy Use Intensity (EUI) targets for
is that to achieve a net zero operational balance,
each building archetype. A ‘top-down’ study of
the EUIs developed via ‘bottom-up’ modelling must
estimated future UK renewable energy generation is
not exceed the budget established by ‘top-down’
cross referenced with a ‘bottom-up’ analysis of best-
analysis, i.e. the energy a building needs to operate
practice design strategies for each building type.
must be matched by the amount of renewable
Whilst the ‘bottom-up’ approach focuses on ‘the
energy that can reasonably be made available to
art of the possible’, the ‘top-down’ modelling looks
that building in 2030 and ultimately in 2050.
Energy reduction
Residential
Office
Renewable increase
Retail
Indust.
Building energy use (kWh/m2)
beyond the building boundary to what is likely to
Othe r
2020
2025
Figure 1.3 - Top-down meets bottom-up approach to energy
Climate Emergency Design Guide
Net zero target 2030
Marrying up top down
and bottom up
1
43
Top Down Modelling
Bottom Up Modelling
To set energy budgets for each building archetype,
The current Part L methodology of setting targets
LETI has compared the 2030 and 2050 forecasts for
using a percentage reduction in emissions from a
available renewable energy generation in the UK
notional equivalent building means that neither the
to the average total floor area of different building
energy demand of proposals nor the potential of
use types. By distributing available energy between
better design, fabric and equipment performance
building types in the same proportions as is seen
are well understood.
today, a range of EUI ‘ceilings’ can be developed for
domestic, office, retail and industrial buildings. The
LETI has therefore modelled the theoretical energy
approach and data sources used for this calculation
demand of different building archetypes, varying
are outlined in further detail in Appendix 1.1.
key design parameters to determine the realistically
SIGNPOST Appendix 1 - Operational energy
achievable EUIs and arrive at a set of ‘optimised’
designs.
The
archetype-dependent
design
parameters include form factor (efficiency of shape),
glazing ratio, fabric performance, ventilation type
and heating/cooling equipment performance.
These design parameters have been set at values
which LETI considers to be achievable and realistic.
Perhaps surprisingly, while the parameters largely go
beyond the current Building Regulations minima, they
are not significantly better than many of buildings
currently being designed.
Modelling
Available
energy supply
- 2030
has
established
‘best-practice’
or
‘optimised’ EUIs, which indicate the lowest energy
demand for each archetype that LETI considers to
be realistically achievable given the technologies
and materials available to designers over the next
decade.
Figure 1.4 - Top down method
LETI
1
44
Setting the Targets
→→ Potential for the deployment of more renewable
Having looked at the problem from both the ‘top
down’ (likely available energy budget) and ‘bottom
up’ (what we can actually achieve), LETI has set a
series of EUI targets for different building archetypes. In
setting these targets, LETI has taken into consideration
factors such as:
the Climate Emergency – i.e. an increase in the
available ‘budget’
→→ The challenge and magnitude of retrofitting
existing buildings and their demand for renewable
energy – i.e. we will not be able to retrofit existing
buildings to the same levels of fabric efficiency
→→ Where we are now – the energy demand of our
current new builds
→→ Best practice right now and what exemplary
schemes are achieving
→→ The scope for further fabric improvements in new
buildings – beyond best practice and towards
exemplar
→→ Potential
technology, at a national scale, as a result of
incremental
improvements
in
technology (e.g. Heat Pump COPs), adoption of
and so we need to accept that they will need to
take a disproportionate share of the ‘budget’
To illustrate this process for the domestic sector, the
chart below shows what LETI believes to be the current
average EUI of new dwellings, best practice, exemplar
schemes and the top-down budget, set against
these is what LETI believes to be an achievable and
pragmatic target for our new dwellings from 2030.
waste water heat recovery systems
140
Current Part
L Average
43
Current Best
Practice
35
Current
Exemplar
'Bottom up'
Modelling
Top Down Budget
(2030)
32
27
Top Down Budget
(2050)
LETI Proposed
Target
Figure 1.5 - Deriving the LETI residential EUI target
Climate Emergency Design Guide
37
35
EUI (kWh/m2.year)
1
45
LETI’s energy use intensity (EUI) targets for each
archetype are as follows:
Residential
35
kWh/m2.yr
Office
55
kWh/m2.yr
School
65
kWh/m2.yr
Figure 1.6 - LETI EUI targets
EUI targets above are based on GIA areas and exclude
renewable energy contribution.
LETI
1
46
What does a ‘Best Practice’
building look like?
The modelling LETI has undertaken shows that
low-energy buildings would fundamentally change
the energy breakdown of our built environment. For
residential buildings, space heating tends to require
most energy due to relatively poor fabric standards.
A highly efficient fabric reduces this significantly.
The diagrams below show how LETI’s best-practice
parameters affect the overall amount and breakdown
of the energy demand in a typical domestic dwelling.
The concept of ‘shoebox’ modelling refers to the
creation of a simplified energy model to inform
decision making at concept design stage. A model
of this type can take the form of a simple shoebox
and can be carried out prior to any formal design
work. The process can provide valuable information
on the proposed building’s energy characteristics,
reveal its sensitivity to different design variables
and help identify the ‘low hanging fruit’ of energy
saving measures.
Heating
Heating
Hot water
Hot water
Lighting
Lighting
Auxiliary energy
Auxiliary energy
Unregulated energy
Unregulated energy
Part L compliant building
Low energy building
Part L compliant building
Low energy building
Figure 1.7 - Residential energy breakdown
?
?
Heating
Heating
Hot water
?
?
Hot water
Cooling
Cooling
Lighting
Lighting
Ventilation
Ventilation
Small power
Part L compliant building
Low energy building
Part L compliant building
Low energy building
Figure 1.8 - Office energy breakdown
?
?
Small power
Other
Other
1
47
140
EUI (kWh/m2.yr
120
140
100
120
80
EUI
100
(kWh/m2.yr)
60
80
EUI
(kWh/m2.yr)
40
60
20
40
0
20
0
Use heat
pump
Eliminate
performance
Use heat
Improve
gap
pump
Eliminateairtightness Install
MVHR
performance
Improve
gap
airtightness Install
MVHR
Current
practice
Improve
window
U-value
Improve
window
U-value
Increase Hot
insulation water
efficiency
Increase Hot
insulation water
efficiency
Improve
form
factor
Improve
form
factor
Reduce
thermal
bridging
Reduce
thermal
bridging
Current
practice
Figure 1.9 - Opportunities to reduce energy consumption in a new residential development
Optimise
glazing
ratio
Optimise
glazing
Low
ratio
energy
design
Low
energy
design
180
160
180
140
160
EUI (kWh/m2.yr
EUI
(kWh/m2.yr)
EUI
(kWh/m2.yr)
120
140
Reduce
internal
gains
Reduce
internal
gains
100
120
80
100
60
80
40
60
20
40
0
20
0
Natural
ventilation
in summer
Natural
ventilation
in summer
Use
demandcontrolled
Use
ventilation
demandcontrolled
ventilation
Relax
setpoints
Relax
setpoints
Use
heat
pump
Use
heat
pump
Current
practice
Current
practice
Figure 1.10 - Opportunities to reduce energy consumption in a new commercial office development
Reduce
glazing
area
Reduce
glazing
area
Improve
U-values
Improve
U-values
Low
energy
design
Low
energy
design
1
48
What does ‘fabric’ mean and
what is important?
A building’s orientation combined with its glazing
The building ‘fabric’ is made up of the materials that
nearly always lead to net heat loss, whereas south
ratio is key to minimising energy demand.
In the
UK over the course of a year, North facing windows
make up walls, floors, roofs, windows and doors. The
more insulation contained within these elements, the
better their thermal performance. However, ‘fabric’
also includes the building’s overall airtightness, as well
as the impact of thermal bridges where the insulation
layer is not continuous.
facing ones can normally be designed to achieve a
net heat gain. However, the amount of South facing
glazing should also be optimised to prevent the risk
of summer overheating. Although East/West windows
can provide useful gains, they can often lead to
overheating due to the low angle of the sun at the
start/end of the day.
Why concept design is critical
The optimum glazing ratios for the UK climate are up
The specification of the fabric, materials and HVAC
to 25% glazed on the southern elevation, no more
systems will all have a significant impact on the
than 20% on the East/West elevations and as little
energy demand of a building. However, even more
as possible on the Northern elevation. The diagram
fundamental are some key design decisions which are
below shows the impact on space heating demand
typically shaped very early on. These are orientation,
as the same building is rotated to place its originally
form factor and glazing ratio.
south facing glazing in a northerly direction. It shows
that purely by changing the building’s orientation, the
space heating demand increases from 13kWh/m2.yr
Annual heating demand (kWh/m².yr)
to 24kWh/m2.yr.
25
N
20
15
10
5
S
SE
E
Main window orientation
Figure 1.11 - Why orientation is important
Climate Emergency Design Guide
NE
N
1
49
A building’s form factor is the ratio of its external
If a building is designed with a poor form factor,
surface area (i.e. the parts of the building exposed
then the fabric efficiency will need to be increased
to outdoor conditions) to the internal floor area. The
significantly to achieve the optimum levels of
greater the ratio, the less efficient the building and the
performance. This will increase costs as more insulation
greater the energy demand. Detached dwellings will
and more efficient systems will be required.
have a high form factor, whereas apartment blocks
will have a much lower form factor and thus will tend
to be more energy efficient. The table below shows
the typical form factors associated with different
design configurations.
Type
Form factor
Bungalow house
3.0
Detached house
2.5
Semi-detached house
2.1
Mid-terrace house
1.7
End mid-floor apartment
0.8
Figure 1.12 - Types of homes and their form factor
LETI
Efficiency
Least
efficient
Most
efficient
1
50
1.4 Implementation
mechanisms (how?)
Regulatory reform
The first and most important step in achieving a net
Establishing a zero carbon training
and research centre
zero built environment is to set out regulations which
In order to facilitate the dissemination of knowledge
are clear, measurable and indicate a pathway to
2030:
→→ The ‘notional building model’ should be replaced
with a series of absolute Energy Use Intensity (EUI)
targets in kWh/m2.yr for space heating, hot water
and overall energy demand at the meter.
→→ Building performance should be measured in
terms of energy rather than carbon as changing
carbon factors constantly move the goalposts.
→→ In addition to an enhanced compliance regime,
actual performance measurements and postcompletion compliance declarations should form
part of future regulations, so that the industry can
start working towards closing the performance
gap.
→→ Clear future energy targets for both retrofit & new
build from 2020 through to 2030 are required, to
enable the industry to prepare and adjust.
→→ Developers choosing to build to higher standards
should be rewarded.
→→ Mechanical Ventilation with Heat Recovery
(MVHR) should be the default ventilation system
in all new buildings, to reduce heat loss through
ventilation and improve indoor air quality.
→→ Local
Authorities
should
be
allowed
and
encouraged to go beyond statutory building
regulations and set energy consumption limits.
→→ To ensure robust and cost-effective routes to net
zero carbon, energy efficiency measures should
be prioritised over on-site renewables.
Climate Emergency Design Guide
and accelerate the adoption of net zero carbon
building in the UK by 2030, LETI recommends
the establishment of a dedicated training and
research centre. The Zero Carbon Hub (http://www.
zerocarbonhub.org/) provided a valuable resource
to the construction industry between 2008-2016 until
funding was cut when the Zero Carbon Homes policy
was abandoned.
LETI recommends the re-establishment of an industry
training and research centre focused on the delivery
of net zero carbon buildings, with four key objectives:
→→ Provide a collaborative platform that strengthens
the understanding and capacity for zero carbon
buildings in the UK.
→→ Provide an industry support hub that facilitates
exchange of best practice knowledge, towards
sustained market transformation.
→→ Deliver a curriculum of industry workshops and
events, focused on enhancing understanding
and application of high-performance design
and construction.
→→ Become a trusted industry resource for design
and construction professionals, and carry out
independent research to identify challenges and
effective solutions associated with zero carbon
performance.
1
51
1.5 Case studies
Office – Enterprise Centre,
Norwich, EUI 70 kWh/m2.yr
Domestic – Lark Rise, EUI 32 kWh/
m2.yr
The Enterprise Centre project inception started in
Lark Rise is an all-electric, two-bedroom guest house
2007, with InCrops. Funding was secured in 2011, the
designed to the Passivhaus Plus standard located on
ground breaking ceremony took place in November
a north-west facing slope on the edge of the Chiltern
2013, and the low carbon concrete base was poured
Hills in Buckinghamshire. The project was completed
in July 2014. The building demonstrates the use of
in 2015. The building has an exceptionally low heating
different, low carbon materials in construction, and
demand achieved by an efficient form factor and high
the potential for local materials in the Norfolk and East
fabric standards. This includes mechanical ventilation
Anglian region.
with heat recovery. A large photovoltaic array means
that, over the course of a year, the building generates
The Enterprise Centre was developed and built to
twice as much energy as it consumes.
the Passivhaus standard, which is recognised as the
most stringent low ‘energy in use’ standard. It moves
beyond UEA’s previous low carbon buildings through
improved insulation, an improvement in air tightness
and there are strong controls on the energy used
within the building. The triple-glazed windows and
the building’s orientation maximise natural light and
minimise heat loss. It has also achieved BREEAM
Outstanding with a score of 93%, a holistic measure of
a building’s attention to sustainable measures.
Figure 1.14 - Lark Rise
Source: Bere:Architects
Figure 1.13 - The Enterprise Centre
Source: Architype
LETI
Climate Emergency Design Guide
LETI
2
Embodied
carbon
53
2
54
Key performance
indicators
1
Meet upfront
embodied
carbon
emission targets
for building
Domestic
Best practice 2020
Best practice 2030
800
<500
<300
Equiv. to 40%
reduction over
baseline
Equiv. to 65%
reduction over
baseline
30% materials
from re-used
sources
50% materials
from re-used
sources
50% materials can
be re-used at end
of life
80% materials can
be re-used at end
of life
kgCO2/m2
elements:
Nondomestic
2
Baseline
1000
kgCO2/m2
Upfront embodied carbon emissions to be
verified post-construction.
Building element targets include products, transport and construction of
substructure, superstructure, MEP, façade and internal finishes (A1-A5).
Figures exclude timber sequestration.
Climate Emergency Design Guide
kgCO2/m2
<600
kgCO2/m2
kgCO2/m2
<350
kgCO2/m2
Equiv. to 40%
reduction over
baseline
Equiv. to 65%
reduction over
baseline
30% materials
from re-used
sources
50% materials
from re-used
sources
50% materials can
be re-used at end
of life
80% materials can
be re-used at end
of life
2
55
Summary
Client/Developer (decision
making)
→→ Adopt a policy that mandates embodied carbon
reduction strategies based on embodied carbon
and whole life carbon analysis on all projects.
→→ Clarify the client’s goals for Net Zero and
Circular Economy developments that embrace
embodied carbon reductions.
→→ Develop
financial
structures
within
the
developer’s business for allocating funds across
R&D/pilot projects.
→→ Identify employees across the client’s business
who will be responsible for Net Zero, circularity
and embodied carbon performance outcomes.
→→ Specify in the project brief that the development
will have low embodied carbon, adopting the
principle of reuse and refurbish over new build
and
requiring
a
comprehensive
embodied
carbon reduction strategy.
→→ Stipulate
embodied
carbon
performance
targets.
→→ Appoint
a
contractor)
design
with
team
experience
(consultant
of
and
conducting
embodied and whole life carbon analysis.
→→ Specify in the contract that the principal
contractor
will
‘as-constructed’
compliance
monitor
and
report
embodied carbon showing
with
embodied
carbon
performance targets.
Policymaker (strategy)
→→ Adopt a policy hierarchy that advocates circular
economy principles: reuse and refurbishment in
preference to demolition and new construction.
LETI
→→ Adopt embodied carbon targets.
→→ Recognise
a
consistent
methodology
and
dataset for embodied and whole life carbon
analysis
e.g.
Royal
Institution
of
Chartered
Surveyors (RICS) Professional Statement Whole
Life Carbon, reporting embodied carbon across
the chosen Life Cycle Stages of EN 15978, as
explained in Appendix 2.1 Embodied Carbon
Reduction Calculations.
→→ Phasing in the mandatory requirement of EPDs
for at least all building parts forming substructure,
frame and upper floors.
Designer (implementation)
→→ Adopt the circular economy principle of reuse
and refurbish before new build (‘retro first’).
→→ Upskill the design team to develop in-house
capabilities and understanding of embodied and
whole life carbon reduction principles and ‘big
wins’, to recognise where the largest reductions in
embodied carbon can be made.
→→ Implement embodied carbon as a sustainable
design metric and calculate embodied carbon
emissions of all projects.
→→ Request
Environmental
Product
Declarations
(EPDs) from all suppliers.
SIGNPOST Appendix 2 - Embodied carbon
2
56
2.0 Introduction
This chapter offers easy-to-follow guidance for clients,
Whole life carbon (WLC): This includes both embodied
designers and policy-makers to better understand
carbon, as defined above, and carbon emissions
how embodied carbon can be reduced in the design
associated with operational energy. The purpose of
and construction of buildings.
using WLC is to move towards a building or a product
that generates lowest carbon emissions over its whole
It is not intended to be an all-encompassing guide
life (sometimes referred to as ‘cradle-to-grave’).
to embodied carbon due to the nature of emerging
Figure 2.1 shows the building life cycle stages, and
knowledge in this field and should always be read
Figure 2.2 shows the interaction between operational
in conjunction with latest guidance and technical
and embodied carbon throughout the lifetime of a
toolkits available, such as those by the UKGBC, RICS
building.
and the RIBA, as listed in Appendix 14 of the Embodied
Life cycle assessment (LCA): A multi-step procedure
Carbon Primer.
to
SIGNPOST Embodied Carbon Primer
Embodied
Carbon:
Carbon
dioxide
quantify
carbon
emissions
(embodied
and
operational) and other environmental impacts (such
other
as acidification and eutrophication) through the life
greenhouse gases are associated with the following
and
stages of a building. The EN 15978 standard is typically
stages:
used to define the different life cycle stages A1-3
→→ Product: extraction and processing of materials,
(‘Cradle to Gate’), A1-3 + A4-5 (‘Cradle to Practical
energy and water consumption used by the
Completion of Works’), B1-5 (‘Use’), C1-4 (‘End of Life’),
factory and transport of materials and products.
D (‘Supplemental’), see Figure 2.1.
→→ Construction: building the development.
→→ In-use:
refurbishment,
In the case of whole life carbon, an LCA assesses
replacement and emissions associated with
greenhouses gas emissions measured in carbon
refrigerant leakage.
dioxide equivalent to also include Global Warming
→→ End
of
maintenance,
life:
repair,
demolition,
disassembly
waste
Potential (GWP).
processing and disposal of any parts of product
or building and any transportation relating to the
Thus the use of predicted CO2 data across the Life
Cycle Stages relevant to the particular development
above.
See Appendix 2.1 for the EN 15978 detailed breakdown
allows comparisons of different options in relation to
of stages.
impact on whole life carbon as well as demonstrating
SIGNPOST Appendix 2 - Embodied carbon
Operational Carbon: Please refer to Chapter 1
Operational
Energy
which
explains
operational
carbon.
SIGNPOST Chapter 1 - Operational energy
Climate Emergency Design Guide
that a certain level of carbon emission reductions
have been met at design stage1.
Environmental
Product
Declaration
(EPD):
An
independently verified and registered document
that communicates transparent and comparable
information about the life cycle environmental impact
of a product 2.
2
57
[C4] Disposal
[C3] Waste
Processing for
reuse, recovery
or recycling
[A1] Raw Material
Extraction and
Supply
[A2] Transport to
D
C
Cradle to grave
including benefits
and loads beyond
the system
boundary
[B7] Operational Water
[B6] Operational Energy
B
cra
dle
co
mp to p
ra
let
ion ctic
[B1] Use
[B5]
Refurbishment
cradle
to gate
[C1]
Deconstruction
and Demolition
Manufacturing
Plant
Reuse
Recovery
Recycling
Potential
cr
to ad
gr le
av
e
[C2] Transport to
Disposal Facility
[A3]
Manufacturing
and Fabrication
A
al
[B2] Maintenance
[B4] Replacement
[A4] Transport to
Project Site
[A5] Construction
and Installation
Process
[B3] Repair
Figure 2.1 - Life cycle assessment (LCA)
Diagram adapted from Hawkins\Brown using illustrations from Open
Systems Lab 2018 licensed under Creative Commons CC-BY-ND
Operational carbon
Practical completion
Replacement and maintenance
Operational
End of life
Carbon emissions (kgCO2)
Embodied carbon
emissions
0
10
20
30
40
50
60
Use stage (years)
Building lifecycle
Figure 2.2 - Graph showing interaction between operational and embodied carbon throughout the lifetime of a building
LETI
2
58
2.1 Contribution to zero
carbon (why do it?)
In the UK, buildings account for 49% of greenhouse gas
Figure 2.4 shows the breakdown of the whole life
emissions. Of the annual carbon emissions associated
carbon stages of an office, residential development
with buildings about 80% is associated with ongoing
and a school. The pie charts to the left show the
operational carbon emissions relating to the existing
breakdown when the development is built to current
building stock. The remaining 20% is related to the
Building Regulation levels, in this case the operational
embodied impact of new construction.
energy makes up by far the largest proportion of
whole life carbon. The pie charts to the right shows
Addressing climate change has traditionally focused
the breakdown of whole life carbon when the
on reducing carbon emissions from operational
development is ultra-low energy (the standard that
energy consumption. However, as buildings become
is set out in the operational energy requirements in
more energy efficient and electricity generation
the archetype pages in the introduction). Due to the
decarbonises, operational carbon of new buildings
reduction in operational energy, the product stage
will significantly reduce. This means that embodied
(A1-A3) makes up the largest proportion of whole life
carbon will represent a higher proportion of whole life
carbon.
carbon (WLC) than it used to. Thus embodied carbon
will become significant and can represent 40-70% of
SIGNPOST Chapter 0 - Introduction
whole life carbon in a new low carbon building. See
Figure 2.3 that shows the magnitude and breakdown
of whole life carbon.
Whole life carbon (kgCO2e/m2)
2500
Operational Carbon
Embodied Carbon
2000
Operational
Trajectory
1500
1000
Embodied
Trajectory
500
0
Operational
Current
Ultra-low
Carbon
Building
energy with
Scenario
Regulations Gas Boiler
Ultra-low
Ultra-low
energy with energy with
Heat Pump Heat Pump
Ultra-low
energy with
Heat Pump
Embodied
Carbon
Scenario
Not
considered
Embodied
Carbon
Reductions
Future
Embodied
Benchmark
Not
Not
considered considered
Total Split
Currently Achievable
2030 Target
Figure 2.3 Diagram showing
operational
and embodied
carbon and
trajectories
2
59
Building compliant with current
Ultra-low energy building
Building Regulations
(achieves target set out in
Archetype pages, Chapter 0)
1%
1%
16%
2%
1%
Office
28%
15%
34%
32%
66%
2%
2%
1%
2%
2%
21%
Medium
scale
9%
residential
23%
<1%
50%
20%
67%
1%
4%
1%
2%
21%
School
10%
1%
<1%
31%
44%
20%
67%
1%
2%
Products/materials (A1-A3)
Transport (A4)
Construction (A5)
Maintenance and
replacements (B1-B5)
Operational energy (B6)
End of life disposal (C1-C4)
Figure 2.4 - Breakdown of whole life carbon in further detail for typical
office, medium scale residential and school developments over 60
years.
2
60
2.2 Current challenges
2.3 Key components/
solutions (what?)
To date, most of the focus has been on reducing
This section identifies clear actions that can be taken
operational carbon emissions. As a result, the
to reduce the embodied carbon of a building and its
development of embodied carbon calculations has
constituent elements. Primary actions are shown in
lagged. The first challenge, therefore, is to improve
Figure 2.6 aside and Figure 2.8 overleaf summarises
industry understanding of embodied carbon, and
the overarching aims and approaches for different
then to focus on the elements that represent the
building elements, set out in the embodied carbon
largest contribution within a building project.
Primer Appendix 6 - Rules of Thumb.
SIGNPOST Embodied Carbon Primer - Appendix 6
Other challenges include:
→→ Lack
of
information
and
transparency
on
of
methodology
for
materials in products
→→ Lack
of
Aims and Approach:
consistency
calculating embodied carbon
→→ Lack of available data from case studies
1.
Build less: Refurb and re-use
2.
Build light: Consider the building structure
3.
Build wise: Longevity and local context
4.
Build low carbon: Review material specifications
5.
Build for the future: Assess end of life and adaptability
6.
Build collaboratively: Involve the whole team
Embodied Carbon Baseline Emissions
Embodied carbon emissions
after reduction measures
Upper Floors
Foundation
Envelope
Frame
Piling
Internal walls
Ceiling Finishes
Floor finishes
External works
0
5
10
15
Percentage of Embodied Carbon (%)
Figure 2.5 - Illustrative Embodied Carbon reduction potential (Study by Mirko Farnetani)
20
25
2
61
Primary Actions
Build less
Build light
Build wise
Build low
carbon
Build for the future
Build
collaboratively
→→ Is a new building necessary to meet the brief, has retrofit been considered?
→→ Can existing materials on or near the site be used?
→→ Has the brief been interrogated against client need and represents the most efficient
solution?
→→ Can uses be shared or spaces be multi-functional?
→→ Carry out a material efficiency review - are all materials proposed necessary?
→→ Seek to simplify the design - simple designs usually means less embodied carbon.
→→ Reduce the weight of the dead loads where possible.
→→ What loadings are really required to meet the brief?
→→ Can long spans be restricted?
→→ Ensure longevity of material and systems specifications.
→→ Review material efficiency options like designing to standard building sizes or for a
repeating module.
→→ Structural members should be designed for 100% utilisation rate where possible.
→→ Analysing a site is an important activity at the start of a project and this can be extended
to the identification of ways of reducing embodied carbon. Possible opportunities
include:
→→ There may be existing structures or buildings that can be reused or become a
source of recycled materials.
→→ There may be locally sourced material options, reducing transport to site while
allowing architectural expression of the context.
→→ Designing a project around a site topography, reusing excavated soil and reducing
the amount removed from site.
→→
→→
→→
→→
Reduce the use of high embodied carbon materials.
Identify ‘Big ticket Items’ and focus on the big wins first including structure and envelope.
Consider natural and renewable materials.
Explore Design for Manufacture and Assembly (DfMA) solutions if this reduces embodied
carbon.
→→
→→
→→
→→
Ensure future uses and end of life are considered and adaptability is designed in.
Consider soft spots in the structure.
Consider regular structural grid and future-proofed risers and central plant space.
Mechanically fix systems rather than adhesive fix so they can be demounted and re-used
or recycled, supporting a circular economy.
→→ Explore methods of creating longevity for materials without additional coatings, as they
can reduce the recyclability of the material.
→→ Solutions must involve the whole design team and the client.
→→ Use ‘rules of thumb’ data to drive decision making in meetings, especially in the early
stages of design.
Figure 2.6 - Primary actions to reduce embodied carbon for a whole building
2
62
MEP
Substructure
15%
Office
Facade
17%
Figure 2.7 shows the relative proportions of embodied
carbon by building element.
16%
It is important to consider not just the proportion
48%
4%
Internal
Finishes
of embodied carbon per element, but also the
Superstructure
Facade
scale
residential
Internal
Finishes
the elements. At RIBA Stage 3 a detailed whole
this, a study shall be undertaken that identifies the
Substructure
13%
potential total embodied carbon reductions of all
life carbon study shall be undertaken. As part of
MEP
4%
Medium
Proportions of embodied carbon
by building element
breakdown of embodied carbon by element and
the carbon reductions that could be achieved for
21%
each element. This helps to identify ‘big ticket items’ –
where the greatest embodied carbon reductions can
16%
be achieved.
46%
Figure 2.5 (on the previous page) is an example of
Superstructure
the results of this type of assessment for a typical
mixed
13%
Facade
School
17%
22%
Internal
Finishes
used
development
(commercial
and
residential). It is evident that the top five building
MEP
Substructure
31%
parts (Piling, Foundation, Frame, Upper Floor and
Envelope) provide the greatest embodied carbon
reduction opportunities and thus should be the focus.
Nevertheless, the remaining bottom items (ceiling
17%
Superstructure
finishes, internal walls, floor finishes and external works)
should also be considered for establishing the project
embodied carbon reduction strategy.
Figure 2.8 showcases ‘rules of thumb’ for reducing
embodied carbon by building element and identifies
Figure 2.7 - Embodied Carbon breakdown per element (Cradle
to Gate).
areas where a large benefit can be found, this is a
summary Appendix 6 of the LETI Embodied Carbon
Primer.
SIGNPOST Embodied Carbon Primer - Appendix 6
2
63
Reductions to embodied carbon by element
Structure
(Sub and super
structure)
→→ Compare the embodied carbon options for sub and superstructure at an early stage to
identify an optimum solution.
→→ Typical bay studies for the horizontal and vertical grid should be conducted at concept
stage for different material arrangements to determine the impact on the total embodied
carbon for each framing arrangement.
→→ A structural rationalisation study should be conducted to determine the impact on overall
material quantity versus efficiency in construction/fabrication.
→→ Reduce the weight of structure where possible through voids.
→→ Maximum embodied carbon quantities should be specified for structural components.
Targets can be achieved by cement replacement such as GGBS, low carbon concrete
mix design, low carbon materials and using recycled/repurposed materials.
→→ Structural frame should be considered to have a dual purpose, i.e. the structure could
serve as a shading device rather than introducing additional shading elements to control
solar gain.
→→ Explore recycled sources of material.
Envelope
(Facade and
roof)
→→ Carry out embodied carbon comparisons on typical construction bays during early
design stages where decisions can be guided by benchmarks / data.
→→ Remember that it is the hidden parts (for example metal secondary framing) of a build up
that often contain the most embodied carbon.
→→ Where metals are used, limit their use and ensure they can be removed and recycled at
end of life.
Mechanical,
Electrical and
plumbing
(MEP)
Finishes and
Furniture
Fixtures and
equipment
(FF&E)
Design for
Manufacture
and Assembly
(DfMA)
→→
→→
→→
→→
Avoid over-provision of plant - a detailed load assessment must be undertaken.
Typically, fewer and simpler systems will reduce embodied carbon.
Explore options for plant room locations which reduce duct runs.
Design for deconstruction and recycling as MEP is typically replaced 2-3 times during the
lifespan of a building.
→→ Specify refrigerants with low Global Warming Potential (i.e. <150) and ensure refrigerant
leakage is carefully considered in the whole life carbon analysis.
→→
→→
→→
→→
→→
→→
→→
→→
Consider eliminating materials where not needed e.g. by exposing services.
Utilise self-finishing internal surfaces like timber.
Consider the cleaning and maintenance regime to be undertaken.
Ensure the fit out requirement is clearly understood to avoid FF&E to be replaced when the
first tenant moved in.
Carefully compare products based on EPD data, recycled material and also avoidance
of harmful chemicals like formaldehydes and VOCs.
Consider the replacement cycle and specify for longevity.
Choose products that do not rely on adhesives so fabrics or finishes can be replaced.
Be wary of trends that are likely to date and require early replacement.
→→ Compare embodied carbon of DfMA solutions with standard solutions.
→→ If DfMA is to be used, identify the elements by the end of RIBA Stage 2. Examples include,
bathroom or WC pods, plant modules, facade elements, repeatable rooms, pre-fabricated
structural elements including twin wall, columns and planks.
→→ Engage the supply chain early.
→→ Lightweight materials are preferable for transportation purpose.
→→ Ensure the repeatable systems are designed for deconstruction.
Figure 2.8 - Primary actions to reduce embodied carbon for each building element
2
64
2.4 Implementation
mechanisms (how?)
Advice for designers
Procurement
Appendix 1 of the Embodied Carbon Primer discusses
LETI believe that public procurement, responsible
in more detail how the designer can make low
for 25% of all UK construction procurement annually,
embodied carbon strategies most attractive to clients
should lead the way for best practice nationally. The
and lays out the crucial times to frame these within
legal framework for public procurement (particularly
the project:
Public Contracts Regulations 2015) is explicit that
→→ The
first
meeting:
Understanding
project
‘all public procurement must be based on value
priorities such as low cost, long-term ownership/
for money, defined as “the best mix of quality and
maintenance.
effectiveness for the least outlay over the period
→→ When being appointed: Ensure that carbon
of use of the goods or services bought”. However
analysis is integrated into the scope of services
designers and industry experts suggest that a life-
and the design programme as well as allowing
cycle approach is rarely undertaken.
for any associated fees for consultants. Key
discussion points with the client can include:
Procurement should ensure that carbon becomes
secondary benefits of reducing carbon, New
a measurable aspect of the specification, such that
London Plan, BREEAM and LCA.
however the building is constructed, carbon forms
→→ When looking to reduce construction costs (value
engineering): Weigh up design aspirations with
part of the contractual obligation of those designing
and building it.
core low carbon strategies and material quantity/
quality considerations, especially in relation to
The form of procurement impacts the agency of the
maintenance. Look at the latest technologies
designer in maintaining low carbon strategies, and
and systems for opportunities to reduce costs.
different forms of procurement will prioritise different
→→ When the building is completed: Post-construction
aspects, e.g. cost, time, quality, risk, finance etc. It is
evaluation is key to building knowledge and
useful to align carbon reduction strategies to other
making
project priorities. Appendix 5 of the Embodied Carbon
improvements.
Ensure
appointments
allow for this.
Primer contains a table of suggestions of low carbon
strategies associated with the procurement priorities
SIGNPOST Embodied Carbon Primer - Appendix 1
listed above.
SIGNPOST Embodied Carbon Primer - Appendix 5
Climate Emergency Design Guide
2
65
2.5 Case study
Details on Implementation
mechanisms for policy makers
Hub 67 - LYN Atelier
→→ Create a national embodied and whole life
material collected in shipping containers left after the
carbon database (e.g. the Dutch Nationale
Milieudatabase) in support of planning policies
mandating embodied and whole life carbon
assessment.
→→ Review the procurement framework awarding
criteria for public buildings and infrastructure, to
incorporate embodied and whole life carbon
targets and wider social/economic responsibility
in terms of life cycle costs within the scoring
system.
→→ Include requirements on embodied and whole
life carbon in building planning and approval
frameworks with consent contingent on the
subsequent reporting of performance against
the design stage target.
→→ Mandate a two-fold verification system: at
‘Hub 67’ is a temporary community centre made from
London Olympics 2012. LYN Atelier won the bid from
the Olympic Delivery Authority to deliver a project
made from re-used building components for a sum
of £350,000. The main structure of the community
centre was constructed from glazed and insulated
composite metal panels salvaged from the banks and
food vending machines from the Olympic grounds.
The main challenge was the complete lack of
information on the performance criteria (thermal and
other) of the materials. This approach relied heavily
on the experience and expertise of the designers and
construction team, who were required to declare the
reformulated construction systems ‘fit for purpose’
in the absence of any manufacturer certification or
guarantees.
the Design Stage and at Practical Completion
Stage. This would build on planning policies
that mandate embodied and whole life carbon
assessment and adoption of target benchmarks.
→→ Adopt planning policy that requires Environmental
Performance Declaration (EPDs) for the majority
of building parts forming substructure, frame and
upper floors.
Figure 2.9 - Hub 67
Source: Re-use Atlas Duncan Baker Brown
2.6 References
1 - Athena, Sustainable Material Institute definition
2 - Environdec - International EPD System
LETI
Climate Emergency Design Guide
LETI
3
Future of heat
67
3
68
Key performance
indicators
1
2
3
4
Climate Emergency Design Guide
Ensure that heating and hot water
generation is fossil fuel free.
The average carbon content of heat supplied
(gCO2/kWh.yr) should be reported in-use.
Limit the peak heat loss for heating
(including ventilation) to 10W/m2.
Limit the dead leg of hot water pipework to 1 litre.
Use ‘Green’ Euro Water Labels for hot water outlets (e.g.:
certified 6 L/min shower head – not using flow restrictors).
3
69
Summary
Client/developer (decision
making)
to other buildings (e.g. for difficult-to-upgrade
existing stock) via heat sharing (ambient loop)
networks.
→→ Highlight the need for passive heat gain, resulting
in smaller, simpler heating and hot water systems.
→→ Prioritise reduced fabric heat loss so that
incidental room heat gains can become primary
heat source.
→→ Mandate cost savings from reduced heat systems
subsidise improved fabric and reduced hot water
demands.
→→ Require reduced occupant fuel bills, both for
energy
consumed
and
associated
systems
service charges.
→→ Reduce room small power requirements to reflect
Smart ICT fit-out and in-use feedback i.e. ~8W/
m2. Likewise, specify individually controlled task
lighting and less blanket uniform lighting i.e.
~4.5W/m2.i
zero carbon solutions.
→→ Ensure all district heating networks have roadmap
to 2030 zero carbon in place.
Designer (implementation)
→→ Use the LETI Heat Decision Tree at concept design
stage and again at developed design stages.
(See Figure 3.5).
→→ Use
high
levels
of
thermal
insulation
and
airtightness for all building types to limit the
installed peak heat loss, typically to ~10W/m2.
→→ Limit the installed peak capacity of domestic hot
water (DHW) heating plant to typically ~6W/m².
outlets for domestic hot water and ensure a
maximum 1 litre volume limit in dead-legs.
→→ Set locally specific overall performance criteria
and avoid being prescriptive about system type.
the
selection of building types demonstrating net
→→ Use European Water Label (EWL)ii ‘Green’ rated
Policymaker (strategy)
→→ Require
→→ Prepare example planning submissions for a
same
building
fabric
energy
standards for all buildings in anticipation of
potential future change of use. This reflects
→→ Select system designs that smooth out peak
demands to help ease grid capacity constraints
and
reduce
required
installed
capacity
electrical storage, operating diversity, etc.
continued convergence between workplace
and
residential
small
power,
lighting
and
occupancy levels.
→→ Prescribe the capture of waste heat (e.g. air
conditioning heat rejection) to make it available
i - A key heating performance gap is because SBEM’s
understated heat losses assume oversized unregulated
room gains are responsible for satisfying much of the
regulated heat demand.
ii - New EU water outlet rating system
LETI
-
harnessing thermal mass, hot water storage,
3
70
3.0 Introduction
3.1 Contribution to zero
carbon (why do it?)
The way we deliver heat must dramatically change if
Heat demand currently accounts for more than 40%
we are to meet our net zero carbon target.
of UK energy consumption by end use2 (see Figure 3.1
opposite), with the vast majority coming from fossil
De-carbonising
heat
energy
is
a
multifaceted
fuelled natural gas.
challenge and must be considered within a wider
context than has previously been the case. Other
All-electric solutions seem to be a compelling, readily
large sectors like transport will also be seeking to
available and a relatively simple means of delivering
access the same renewable alternative energy
net zero carbon heat.
sources, arguably with fewer alternative zero carbon
However,
options available to them.
the
challenge
of
using
electricity
is
illustrated by how heat demand dwarfs the current
Alternative energy carriers like hydrogen have been
electrical supply capacity. This is compounded by
suggested for heat generation, but so far there is no
seasonal peaks in heat demand that exceed the
indication that this technology could serve more
total electricity supply capacity by a factor of four
than a few niche sectors. Not least is the lack of any
(see Figure 3.2 opposite). Even a complete theoretical
national strategy for implementing the high predicted
switch
gas to hydrogen switchover costs .
to
electric
heat
pumps
with
ambitious
On the other
operating coefficient of performance (COP) of 4
hand, heat for buildings can be derived from a wider
would necessitate a doubling of the current electrical
range of alternative energy carriers and sources than
grid capacity. This is before consideration of other UK
is the case for many other energy-requiring sectors.
sectors also switching to electricity consumption.
1
This includes the use of waste heat, much of which is
often produced within the building requiring the heat
To plan a way forward, it will be necessary to have
or heat available from other buildings close by.
an indication of how much renewable grid electricity
can realistically be expected to be available for
Perhaps the greatest opportunity is simply to reduce
delivering heat in the future. LETI have carried out an
the amount of heat actually needed to deliver the
initial study for total electricity consumption from the
required level of amenity, be it through point-of-use
grid. Elsewhere, national studies3 have also started to
demand reduction, thermal insulation, or similar
explore this issue.
measures.
SIGNPOST Appendix 3 - Future of heat
The Energy Use (EUI) targets set out in this document
for offices is no more than 55 kWh/m2 annually of
site imported renewable electricity supply, while
for residential buildings it is 35 kWh/m2. This limited
renewable electricity supply would need to serve all
SIGNPOST Chapter 1 - Operational energy
SIGNPOST Appendix 1 - Operational energy
Climate Emergency Design Guide
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71
3.2 Current challenges
building functions, including small power, computing,
The constraint on access to renewable electricity
lighting etc., as well as heating and cooling. The
requires a fundamental rethink of how suitable
lack of alternative options for many of these other
heating strategies are assessed.
in-building operational uses of electricity means that
have developed a Heat Decision Tree assessment
heating requirements must inevitably be reduced by
methodology
taking full advantage of all possible other point-of-use
(see Figure 3.5). This reflects the large number of
reductions, including thermal insulation, use of waste
opportunities and constraints. The following sections
heat sources, etc.
follow the process order outlined in the Heat Decision
for
appraising
Therefore, LETI
heating
options
Tree.
?
14%
Heat
41%
Transport
?
45%
Other - largely electricity
Figure 3.1 - UK energy demand 2011
Source: Energy
Research council
Challenges for the decarbonisation of heat: local gas demand
vs electricity
supply Winter 2017/2018
Peak heat demand
200 GW
Gas - local distribution
zone demand
Maximum week
Median week
150 GW
100 GW
Peak electricity supply
50 GW
GW
Mon
Tues
Wed
Thur
Fri
Sat
Electricity - supply plus
embedded generation
Maximum week
Median week
Sun
Britain’s local gas demand and electrical system supply - median and maximum demand weeks. The
week dating 22nd to 28th is the median demand week for 2017-2018 heating season. The week dating
Figure 3.2 - Challenges for the decarbonisation of heat: local gas demand vs electricity supply winter 2017/2018.
26th February to 5th March represents the maximum demand week of the 2017-2018 heating season.
Source:
Energy
Research Research
Council. Britain’s
local gas demand and electrical system supply - median and maximum demand weeks. The week
Source:
UK Energy
Council
dating 22nd to 28th is the median demand week for 2017-2018 heating season. The week dating 26th February to 5th March represents the
maximum demand week of the 2017-2018 heating season.
LETI
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72
3.3 Key components/
solutions (what?)
Reduce heat demand at point of
use
The target maximum installed output capacity of DHW
This is fundamental for reducing system energy demand
recharge for most residential and other high DHW use
- before considering heating system alternatives.
Smaller demands open up new opportunities, not
least the potential of no requirement for any heating
system at all in certain circumstances.
heating plant is expected to be about 6 W/m2 of floor
area. This will require hot water storage with trickle
building types. If heat pumps are used, 9 kWh/m2.yr
renewable electricity would be required, either from
the grid or from an on-site generated supply.
LETI recommend to design out the need for cooling.
The proposed target for the reducing space heating
requirement is as a maximum installed heating plant
output capacity of approximately 10 W/m of floor
2
area. This approximately equates to typical incidental
room heat gains (people, appliances etc.). This means
that under typical circumstances the heating system
does not need to run and is only required as back-up.
This same limit is proposed for all building types
to allow for future change of building use without
wholesale change to the base heating system. If
heating plant output capacity is provided via heat
pumps, this is expected to require about 6 kWh/m2.yr
of renewable electricity, either from the grid or from
So, just as residential developments now tend to
need limited window area proportions to avoid
mechanical cooling due to solar gain, the same
principles should be applied to offices and other
building types to likewise avoid mechanical cooling
needed to removed solar gain. Typically windows are
expected to be no more than 35% of facade area to
be enough to maintain daylight levels. In addition,
avoiding oversized windows helps reduce winter
heat loss. For buildings where cooling is required for
normal occupancy (i.e. excluding process loads),
it is expected that those same heat gains would
consequently also reduce the above annual heating
an on-site generated supply.
demand such that the same annual energy demand
Minimising domestic hot water (DHW) demand is
These targets are by convention given per floor area
particularly important because of the adverse energy
and carbon implication of delivering the higher
temperatures DHW typically requires compared to
space heating systems. All outlets should be ‘Green’
rated according to the new European Water Labelling
(EWL) system. For example, for a shower, this equates
to a maximum flow limit of 6 litres per minute (coupled
with a suitable pressurised water supply system and
without flow restrictors). Domestic hot water pipework
should be designed to ensure there are no ‘dead
legs’ containing more than 1 litre.
target also includes the cooling input energy needs.
and thus, in terms of minimising overall heat demand,
it is also important to minimise the building floor area
required.
Given the expected constraints on grid-delivered
renewable electricity, particularly during periods
of peak heat demand, building systems should be
configured to harness heat at the lowest temperatures
possible and hence maximise heat pumps efficiencies.
While there are heat pumps that can operate at
higher temperature differentials between their heat
source and heat sinks, generally they all operate
significantly more efficiently at lower temperature
differentials and so require less grid power.
Climate Emergency Design Guide
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73
Minimise systems temperatures
A common example of how this can be achieved
In general, high temperatures in heating systems
of radiators for space heating. Whereas radiators
are synonymous with fossil fuel combustion as this is
the most common way used in the past for heating.
However, given the path to net zero carbon requires
a move away from fossil fuel combustion, minimising
system temperatures is a crucial step in that direction.
Lower system temperatures allow for increased system
efficiencies and lower losses in conversion, storage
and distribution of heat. A wide range of renewable
technologies
(heat
pumps,
solar
thermal
etc.).
work most efficiently at relatively low temperatures.
In addition, available waste heat sources are
also typically at lower temperatures. Therefore,
minimising system temperatures effectively opens
up opportunities for integrating a wider range of low
and zero carbon heating sources and can have a
significant impact on the overall carbon emissions of
is by specifying underfloor heating (UFH) instead
typically require a water flow minimum temperature
of 45-55˚C, UFH can operate at flow temperatures as
low as 25-35˚C because of its larger surface area for
transferring the required heat into the room. This larger
warm surface area also means comfort levels can be
achieved at lower room air temperatures.
Following the same principle, room cooling (i.e. the
removal of heat for potential use elsewhere) also
operates more efficiently where there is a larger
room surface area to deliver the required coolth.
This similarly provides a larger radiant cooling effect
and so achieves room comfort levels at higher
air
temperatures.
It
additionally
allows
turn improve heat-pump efficiencies.
a heating and hot water system.
Space heating peak
Domestic hot water peak
Plant capacity
10 W/m
6 W/m
16 W/m2
2
2
Equiv. to 6 kWh/m2.yr
Equiv. to 9 kWh/m2.yr
renewable electricity from
renewable electricity from
the grid
the grid
Figure 3.3 - Plant capacity calculation
LETI
higher
temperature cooling distribution systems, which in
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74
Lean design
heat pumps are one example. Also, waste heat from
Rather than applying the generous oversizing margins
be reused as a heat source for space heating and
buried in conventional rules of thumb when carrying
out heat loading calculations, detailed load modelling
will provide better predictions of energy use and help
size plant requirements more accurately. Furthermore,
sizing heating plant capacity using the 96th percentile
approach rather than providing capacity for the
full load at design conditions, reduces the heat
generation equipment size and increases efficiency
of the equipment in operation. Similarly, sizing and
increased efficiencies are achieved by eliminating
the rounding margins conventionally applied at each
stage of design, plant selection and commissioning.
As the thermal performance of a building improves, it
cooling heat rejection and refrigeration systems can
domestic hot water systems, whilst also contributing
to a reduction in the ‘Urban Heat Island’ (UHI) effects.
There are also opportunities to harness waste heat
at infrastructure level. Sources such as London
Underground ventilation4 and industrial processes
should
be
considered.
Other
sources
such
as
water treatment and waste treatment works offer
opportunities for establishing heat sharing ambient
loop networks by circulating low temperature heat to
nearby developments.
Join a heat sharing network
responds more slowly to drops in outdoor temperature,
Minimising
permitting the use of less onerous outdoor design
creates
conditions. Highly insulated buildings also mean
networks. Demand circuits with lower flow and return
intermittent control strategies deliver reduced benefit
temperatures have a greater opportunity to harness
due to limited room temperature drops during off
waste heat from local sources, which can include
periods. Consequently, a strategy of trickle charge
heat rejection from buildings with cooling demands.
over extended operating hours can greatly reduce
This same heat can then be reused by buildings with
plant capacities and improve energy efficiencies.
a heating demand, at an improved efficiency. This is
demand
opportunities
and
to
system
establish
temperatures
heat
sharing
particularly useful in mixed use developments where
Harness waste heat
there are different heating (and cooling) demand
After considering ways of reducing the heat demand
heat sharing. This also helps reduce ‘urban heat
at point of use and minimising system temperatures,
the next priority should be to harness waste heat from
all available sources in and around the site. Capturing
heat released as a by-product of an existing process
enables this otherwise wasted heat to contribute to
meeting energy demands.
Air source heat pumps (ASHPs), ground source heat
pumps (GSHPs) and water source heat pumps (WSHPs)
are common examples of using heat from the natural
environment. However, waste heat is also available
from activities or processes and can be captured
at different scales. At a building scale, exhaust air
Climate Emergency Design Guide
profiles, offering opportunities for load shifting and
island’(UHI) impacts caused by the heat rejection
from building cooling systems.
This approach implies a step change in operating
temperatures for district level schemes, away from
the current norms for 4th generation district heating
networks operating at 70°C flow and 40°C return or
above, to 5th generation district heat sharing ‘ambient
loop’
networks,
controlled
around
much
lower
working temperatures of between 8°C and 25°C.
These lower temperature networks can benefit far
more readily and cost effectively from any available
low temperature waste heat. See Figure 3.4 opposite.
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75
District heat network operating economics need
very careful consideration where connected to
new high efficiency buildings. When heat demand
is significantly reduced, eventually down to the level
of ‘Heat Autonomy’, where most heat needs are met
from incidental internal gains, there is little energy
delivery cost revenue for the network operator.
Network distribution losses can become larger than
the quantity of delivered heat. This is likely to be
reflected in significant fixed connection and services
charges being the dominant energy bill component.
This suggests that the effort and resource use needed
for district heat networks should be focused instead
on
serving
the
difficult-to-decarbonise
existing
building stock, along with those building which can
Shortlist system solutions
Having investigated the ‘opportunities’ offered by
the site, by harnessing building fabric enhancement,
and by using all possible waste heat sources from the
building and from the locality beyond the immediate
site, a shortlist of possible heat systems should be
tested against the constraints identified in the LETI
Heat Decision Tree.
For net zero carbon, systems dependant on natural gas
and other fossil fuels are expected to be unsuitable.
This includes combined heat and power (CHP) and
gas boilers, as well as hybrid systems that may use
fossil fuels for peak demands. Where the natural
supply surplus waste heat.
1G: Steam
2G: In-situ
3G: Prefabricated
4G: 4th generation
5G: Heat-share
Steam system, steam
pipes in concrete ducts
Pressurised hot-water
system
Heavy equipment
Large “build on site”
stations
Pre-insulated pipes
Industrial compact
substations (also with
insulation)
Metering and
monitoring
Low energy demands
Smart energy (optimum
interaction of energy
sources, distribution and
consumption)
2-way DH
Ambient temperature network
Redistribution of wider range of lower
grade heat sources
Accepts simultaneous cooling heat
rejection and heat supply
Increased heat pump efficiencies
Avoids combustion air emissions
Zero carbon enabled
DH flow
Energy
efficiency
Large scale
solar
District heating grid
Energy efficiency / temperature level
DH return
Biomass
CHP
Industry
surplus
Heat
storage
Heat
storage
Steamstorage
CHP coal
CHP oil
CHP waste,
CHP oil,
CHP coal
Coal
Waste
Coal
Waste
Gas
waste,
Oil, Coal
Local District
Heating
1G / 1880 - 1930
Seaonal
heat storage
Seaonal
heat storage
Large scale
solar
Large scale
solar
Geothermal
Geothermal
CHP
Biomass
Centralised
heat rejection
Centralised
heat pump
Centralised
heat pump
District
cooling
District
cooling
Heat
storage
CHP waste
incineration
Heat
storage
Residual
waste CHP
incineration
Industry
surplus
Industry
surplus
District Heating
District Heating
District Heating
2G / 1930 - 1980
3G / 1980 - 2020
4G / 2020 - 2025
Future
energy
source
PV, Wave,
Wind
surplus,
Electricity
Building
cooling
Building
heating
Heat pump interface
to heat-share network
5G / 2025 - 2050
Figure 3.4 - District heating network evolution
Source : Thorsen, J. E., Lund, H., & Mathiesen, B. V. (2018). “Progression of District Heating – 1st to 4th generation”. 5th generation
adaptation Twinn, C.D.A. (2019)
LETI
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gas network is locally converted to 100% hydrogen
this can be considered but beware that much of
current hydrogen production is itself carbon emissions
intensive and hence not zero carbon. Connecting
to district heating networks that are dependent
on fossil fuels should be avoided unless there is a
declared route-map to zero carbon for 2030. Energy
from waste is another option, however much of the
burned plastics / biomass derivatives emit CO2 that
was previously locked out of the atmosphere. Instead
as part of a circular economy these materials should
be recycled, reprocessed and reused. At this time the
logic of how energy from waste can contribute to a
Heat decision tree
The Heat Decision Tree below highlights the broad
range of issues that the heating system selection
must address, including such non-carbon issues as
avoiding higher energy bills for those least able to
pay. Similarly, air quality issues, particularly in urban
areas, and countering the increase of future UHI,
are likely to preclude combustion processes. Some
of these criteria will vary from region to region and
hence local planning policy will need to define
locally acceptable limits with future trajectories for
progressive improvements.
zero-carbon society has not been established, and
consequently at this time this is not a suitable solution.
01.
Aim
Appropriate
levels of:
• Warmth
• Hot water
OP
02.
Reduce heat
demand at
point of use:
• Enhance
thermal
envelope
(e.g.: 10 W/m²)
• Reduce
hot water
need (e.g.:
EWL 'Green'
outlets)
PO
03.
Minimise
system
temperatures:
• Allows better
system
efficiencies
• Increases
zero-carbon
options
RTU
NI
TIE
S
04.
Harness waste
heat:
• Building
discharges
• Industrial
processes
• Tube,
sewage,
river, etc..
05.
Heat-share
network:
• Heat
rejection
from others
• Waste heat
to others
• Low
temperature
networks
13. Reconsider: Can
demands be less?
Alternative system?
No
Yes
12.
Can peak
demand
management
be
implemented?
Response to
system peak
capacity
constraints?
No
Yes
11.
Does it
minimise
kWh/m²
demand
in-use and
report it?
Figure 3.5 - Heat decision tree
No
Yes
No
Yes
10.
Does it lower
user bills (kWh
+ service)?
Risk check
non-standard
user profiles
09.
Does it avoid
emitting noise,
air and heat
pollution?
CONSTRAINTS
06.
Identify
potential
system
solutions
No
Yes
08.
Is there a zero
carbon
transition plan
in place?
No
Yes
07.
Is it lowest
carbon
option?
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Heat system options
Suitability for zero carbon
Gas boilers / fuel
cells
Not zero carbon because of fossil fuel use. Could be zero carbon if fuelled by
hydrogen created from renewables.
CHP leading with
gas boiler
Not zero carbon because of fossil fuel use. Could be zero carbon if fuelled by
hydrogen created from renewables.
CHP leading with
gas boiler on
district heating
Not zero carbon because of fossil fuel use. Could be zero carbon if fuelled by
hydrogen created from renewables. Beware of relatively high distribution standing
losses when serving low energy buildings.
ASHP with gas
boiler peak loads
on district heating
Not zero carbon because of fossil fuel use. Could be zero carbon if fuelled by
hydrogen created from renewables. Beware of relatively high distribution standing
losses when serving low energy buildings.
Centralised
ASHP on low
temperature
district heat
network with local
WSHP upgrade for
DHW
Potential for zero carbon once grid decarbonised or if powered by on-site
renewables. Beware ASHPs do not operate at their most efficient at high district
heating temperatures. District heat network losses reduced if operating at ‘ambient’
temperature of 18-25oC ideally. Low flow DHW outlets ideally to reduce high
temperature demands. Beware lowest COP efficiencies and reduced capacities
occur are during coldest weather.
Exhaust air heat
pump (EAHP)
with MVHR in
each building /
dwelling
Potential for zero carbon once grid decarbonised or if powered by on-site
renewables. Harnesses only waste heat using 2-stage heat recovery and is
dependent on enhanced thermal envelope and low flow DHW outlets.
Room WSHP units
with building
centralised ASHP
Potential for zero carbon once grid decarbonised or if powered by on-site
renewables. Heat sharing ambient loop water network allows heat recycling
within building. Can connect to district heat sharing network so heat rejected from
cooling systems is redistributed to heat demand buildings.
ASHP for DHW
Potential for zero carbon once grid decarbonised or if powered by on-site
renewables. Be-ware that COP efficiencies are generally quite poor for generating
DHW temperatures. Future CO2 high pressure refrigerants expected to improve
COPs (see Appendix A3.2)
GSHP per building
or on heat share
district system
Potential for zero carbon once grid decarbonised or if powered by on-site
renewables. District heat network reduced losses if operating at 18-25oC ideally.
Better COPs than ASHP in winter, although poorer during summer.
DX / VRV heat
pumps
Potential for zero carbon once grid decarbonised or if powered by on-site
renewables. COP efficiencies are generally poor for generating DHW temperatures.
Unlikely to be compatible with low global warming potential (GWP) refrigerants.
Beware lowest COP efficiencies and lowest capacities during coldest weather.
Direct electric
Unlikely to be compatible with future renewable grid peak demand restrictions.
Likely to increase energy bills significantly. May be suitable as back-up for zero
heating buildings and for very low DHW demands.
Biomass (solid)
boilers
Unlikely to be acceptable in urban areas due to fuel emissions. Harvesting and
delivery also needs to be zero carbon with comprehensive forestry replenishment.
Figure 3.6 - Heat system options table
Definitions:
DHW
Domestic hot water
CHP
Combined heat and power unit (gas-fired)
ASHP
Air-source heat-pump
WSHP
Water-source heat-pump
COP
DX
EAHP
MVHR
ZC
Coefficient of Performance of heat-pump
Refrigerant piped between split units (often reverse-cycle)
Exhaust-air-source heat-pump
Mechanical ventilation heat recovery unit
Zero carbon
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3.4 Implementation
mechanisms (how?)
3.5 Case studies
The LETI Heating Decision Tree has been developed
to provide a clear strategic approach to identify and
19-35 Sylvan Grove, Old Kent Road
implement future-proofed low-carbon heat amenity
32-storey new development including 220 dwellings
as part of delivering zero carbon buildings. It draws
aiming for 69% less carbon emissions than Part L by
together all the major issues needing consideration
operating using ‘Heat Autonomy’.
before agreeing a heat strategy for a building.
Demand
reductions
include
massing
reduced
form factor, enhanced envelope U-value of 0.12W/
The way we deliver heat amenity must dramatically
m2.K, windows of 1.2W/m2.K at 32% of façade area,
change if we are to meet our net zero carbon target.
airtightness of 2m3/m2/hr @ 50Pa test pressure and EWL
De-carbonising heat is a multifaceted challenge and
‘Green’ rated hot water outlets. Installed heating peak
must be considered within a wider context than has
demand of 12 W/m2 with annual heating and DHW
previously been the case.
demand of 13 kWh/m2. Low demand to be provided
by in-dwelling unit containing MVHR, exhaust air heat
Key to addressing this for new buildings will be point-
pump and DHW cylinder with trickle charge system.
of-use heat demand reductions using significantly
The project is zero carbon ready, based on using
more efficient building fabric and hot water use,
decarbonised grid electricity and ‘Paris proofed’
coupled with reuse of low temperature waste heat
requiring less electricity than the anticipated 2050
sources. There are economic payoffs to be made,
allowance.
including smaller heat systems, freeing money for
enhanced building fabric.
Reducing building demand comes to a point where
recovered waste heat can satisfy most heat needs.
This suggests that the effort and resource use needed
for district heat networks should be focused instead
on
serving
the
difficult-to-decarbonise
existing
building stock, along with those building which can
supply surplus waste heat.
Early project discussions about heat are essential, not
least because it involves questions about future fitout
standards and building envelope, long before the
normal selection of a heat system.
Figure 3.7 - Sylvan Grove
Copyright HTA/Joseph Homes
Climate Emergency Design Guide
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3.6 References
Tower Blocks, Enfield Council
1 - The CCC, Hydrogen in a low carbon economy
Comprising over 400 flats in eight 12-storey towers, this
publication/hydrogen-in-a-low-carbon-economy/
[Online] Available from: https://www.theccc.org.uk/
retrofit project was the largest shared ground source
loop array heat pump in England when completed in
2 - Energy Research Council [Online]. Available from:
2018. The array is composed of 16 shared ground loops
http://w w w.ukerc.ac.uk/publications/local - gas-
connected to individual heat pumps installed in each
demand-vs-electricity-supply.html
residential unit via an ambient loop pipe network
without the need for a central energy centre. A hot
3 - Dutch Green Building Council, Paris Proof [Online]
water store in each flat reduces the peak electrical
Available from: https://dgbc.nl/themas/paris-proof
demands and allows a small heat pump to deliver
both hot water and space heating from the equivalent
4 - Greater London Authority, London’s Zero Carbon
of only 40m of borehole length per dwelling.
Energy Resource: Secondary Heat [Online]. Available
from:
https://www.london.gov.uk/sites/default/files/
Overall, the upgrade to the heating infrastructure
gla_migrate_files_destination/130220%20031250%20
resulted in a 30-50% reduction in energy bills for the
G L A % 2 0 Low % 2 0 C a r b o n% 2 0 H e a t % 2 0 St u d y % 2 0
residents and an estimated saving of 773 tCO2/yr.
Report%20Phase%201%20-%20Rev01_0.pdf
Local combustion emissions have been eliminated for
the heating system. With each flat having its own heat
pump, each property is responsible for its own energy
bill, and able to switch supplier.
Figure 3.8 - Sylvan Grove
Source: (https://www.thefutureeconomynetwork.co.uk/englandsmost-innovative-district-ground-source-system-wins-industry-oscar)
LETI
Climate Emergency Design Guide
LETI
4
Demand
response
81
4
82
Key performance
indicators
1
2
3
4
Climate Emergency Design Guide
Develop a demand response strategy.
Design to reduce peak electrical demand.
Incorporate active demand response measures
e.g. thermal storage and set point control.
Influence occupant behaviour with display
and reporting of demand and usage.
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83
Summary
Client/developer (decision
making)
→→ Investigate the potential for energy flexibility in
developments.
→→ Consider rising energy costs and the potential for
an energy flexible building to take advantage of
dynamic pricing in the electricity market. This can
reduce occupant energy bills.
→→ Be willing to invest more on control systems and
metering to build ‘future ready’ energy systems in
your developments.
→→ Set a brief that allows for flexibility in meeting
comfort bands. For example, in an office the
temperature upper limit may be 26 degrees, but
under grid constraints this could be raised to 28
degrees for short periods of time.
Policymaker (strategy)
→→ Require energy flexibility assessments on all
schemes.
→→ Allow for carbon saved from energy flexibility to
contribute towards the sustainability requirements
on a scheme (Appendix 4.5 provides a method
for reporting and auditing).
→→ Set binding targets for minimum energy flexibility
to be achieved in medium to large scale
developments.
→→ Develop an auditing mechanism to ensure
compliance and verification.
LETI
Designer (implementation)
→→ Consider the periods during the day and
throughout the year that the development uses
electricity, not just the total electricity consumed
over the course of the year.
→→ Learn about dynamic carbon factors (variation in
carbon emissions from the grid at different times
of the day and year) and consider them in your
energy and carbon models.
→→ Develop and use tools to model flexibility in the
energy systems and calculate carbon reductions.
→→ Specify high accuracy/resolution metering in
the right places to prove when an energy-use
change has occurred.
SIGNPOST Appendix 4 - Demand response and
energy storage
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84
4.0 Introduction
4.1 Contribution to zero
carbon (why do it?)
Demand side response or energy flexibility refers to
According to the National Grid1 demand side
the ability of a system to reduce or increase energy
flexibility is a contributing factor in allowing more
consumption for a period of time in response to
renewables
an external driver (e.g. energy price change, grid
Electricity networks function most consistently on the
availability).
stable and predictable supply of fossil fuel, hydro and
to
connect
to
electrical
networks.
nuclear power stations. These sources of electricity
Energy storage refers to the ability of a physical
can be switched on when needed to make sure the
system to consume, retain and release energy as
supply matches the demand on the electricity grid.
required. This allows system flexibility in response to
Introducing generation from renewable sources, such
specific energy demands.
as solar and wind, to the grid reduces the carbon
intensity of grid electricity. However, renewables are
Demand response and energy storage can both
naturally intermittent, and their power generation
contribute to net zero carbon at the following levels:
does not necessarily coincide with demand on the
electrical grid.
→→ Building level – maximising the utilisation of
on-site renewables.
→→ Area level – contributing to local grid electricity
system resilience.
→→ National level – allowing for more renewables to
supply the wider electrical network.
Demand response has the following benefits:
→→ When renewable electricity generation is low,
demand response measures reduce the load
on the grid, reducing the amount of peaking
gas plant that must be switched on to meet the
grid demand. This reduces the carbon emissions
In the future, it is predicted that energy costs will
continue to rise.
In order to ensure a more stable
grid it is likely that time of use tariffs will become
associated with the electricity grid.
→→ Demand side flexibility reduces demand variation
and grid instability.
commonplace, penalising the use of energy during
→→ Fossil fuel generation, such as peaking gas power
times of the day with high demand. Buildings that can
plants used infrequently, is very expensive to run.
modify their energy use in real time through the use of
Demand side flexibility reduces the need to keep
demand response and storage systems will be able
this peaking plant in ready for use, resulting in
to reduce occupants’ energy bills. LETI believes that
cost savings.
in the future it would be expected that these systems
are incorporated in every new building. Figure 4.1
The National Grid is aiming to further increase the
provides a graphical illustration of this process.
use of renewables, increasing the need for demand
side flexibility 2.
Maintaining a balanced grid is
vital: it is critical that instantaneous supply matches
instantaneous demand to ensure both that power
cuts do not occur but also to maintain the correct
voltage and frequency to ensure that electrical
equipment connected to the grid operates correctly
and efficiently.
Climate Emergency Design Guide
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85
The other way that the market regulates the balance
periods consumers are paid to consume excess grid
is using price. Traditionally, large electrical retail
electricity.
companies simply give consumers a flat rate and pay
the market price themselves. However, increasingly
As well as balancing at a national scale, there is also
there are companies offering consumers the option
a local grid resilience issue. The increasing uptake of
to increase their exposure to market prices, and
electric vehicles and heating mean local grids are
the peaks and troughs that are associated with it.
becoming increasingly strained. Older, smaller cables
Buildings that have demand response capability will
and substations will require expensive upgrades.
be able to take advantage of flexible pricing, saving
These take time, cost money and cause a lot of
significant sums of money. Flexible pricing can lead
disruption during the works; so being able to retain
to the price of energy becoming negative during
existing infrastructure without upgrades is more cost
periods of high supply and low demand. During these
and carbon efficient.
ity
electric system re
silie
grid
al
nc
c
e
Lo
Peak
grid
supply
d
ce
du
re
us
ag
e
grid feeds buildings
building surplus tops up grid
enhanced fabric
Building level
Area level
National level
Figure 4.1 - Demand response operates at the building level and national level
LETI
Reduced
grid
supply
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86
4.2 Current challenges
4.3 Key components/
solutions (what?)
Due to the financial rewards and increased resilience
The following key components contribute to demand
many companies are retrofitting demand response
response and energy storage:
systems into their buildings. Due to a lack of regulation,
1.
Peak reduction
a
modelling
2.
Active demand response measures
frameworks, and the fact that most of the benefits go
3.
Electricity generation and storage
to the operator rather than the developer; demand
4.
Electric vehicle (EV) charging
response systems are rarely planned in at the design
5.
Behaviour change
stage though. Instead, they are often introduced as
6.
Microgrids
lack
of
representation
in
carbon
retrofits, which prohibit most buildings from taking full
advantage of their inherent opportunities for flexibility.
Peak Reduction
Further challenges include:
Passive measures and efficient systems should always
→→ Lack of understanding about demand response
take priority in the design process. They reduce
and energy flexibility in the design team and how
demand on the grid in the first instance.
to include this in buildings.
→→ Lack of industry standard metrics to measure the
‘flexibility’ of buildings.
of
case
studies
showcasing
response measures.
→→ Heating peak reduction – This includes: high
performance fabric, a good level of airtightness,
→→ Lack of targets that define what good is.
→→ Lack
Peak reduction measures include:
demand
a compact form factor and thermal mass. An
efficient heating system also reduces the heating
peak demand.
→→ Cooling peak reduction – Designing out the
need for cooling has a large impact. If this is not
possible, then the mitigation measures described
in Chapter 1 can reduce the cooling annual
demand and importantly the cooling peak. For
example, this includes appropriate glazing ratio,
external shading, thermal mass, efficient cooling
system and efficient lighting.
→→ Domestic hot water peak reduction – This includes
low-demand outlets, reducing distribution heat
loss and installing an efficient heating system.
SIGNPOST Chapter 1 - Operational energy
SIGNPOST Chapter 3 - Future of heat
Climate Emergency Design Guide
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87
Having a high performance building fabric will
longer periods of time. Figure 4.2 shows the impact
allow internal temperatures to be maintained at
that a thermally efficient fabric has on reducing the
comfortable levels without active heating or cooling.
peak heating load.
This reduces the energy required from the grid for
Poor Fabric
Internal
Temp
(ºC)
Heat
Load
(kW)
Poor Fabric
heat load shifted
to non peak time
Internal
Temp
(ºC)
Heat
Load
(kW)
15
15
22
22
20
20
18
18
0000
0600
1200
1800
2400
0000
0600
Good Fabric
Internal
Temp
(ºC)
Heat
Load
(kW)
22
20
20
18
18
1800
Good Fabric
heat load shifted
to non peak time
Internal
Temp
(ºC)
22
1200
2400
Heat
Load
(kW)
3
0000
0600
1200
1800
2400
3
0000
0600
1200
Poor/ Good Fabric Key
Internal Temp(ºC)
Figure 4.2 The impact that a thermally efficient fabric has
on reducing the peak heating load for an example day.
Average Int Temp(ºC)
Heat Load (kW)
Shifted Heat Load (kW)
Max. Heat Load (kW)
LETI
1800
2400
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Connection agreement reduction
Thermal Storage
One of the major costs of a development can
→→ Thermal storage of coolth or heat can be
often come from the connection agreement to the
integrated into a communal system or individual
electricity grid District Network Operator (DNO). Using
system within a building.
a combination of the methods listed to cap the peak
→→ In winter the electricity grid is more likely to be
energy consumption could allow a developer to
constrained at periods when homes are heated
negotiate a smaller energy connection agreement
and hot water demand is high, e.g. first thing in
cost. In the future, if an asset is designed and built
the morning. Thermal storage disassociates when
which is helpful to the energy network operation, and
heat is produced from when this heat is required.
that connection would benefit the DNO, connection
→→ The thermal store can be charged at a period
when the grid is unconstrained or low carbon,
cost could be reduced.
then used to provide heating and hot water
Active demand response
measures
during peak grid times without putting extra load
on the grid.
Once an efficient passive design is in place, there is
often an opportunity for active demand response
systems to be considered.
These systems would
bring further carbon savings, better energy network
resilience, more appropriate time of use consumption
(e.g. peaks) and financial rewards. These measures
reduce the electricity consumption for a certain
Large building loads
→→ Any given organisation may have opportunities
for reducing other large loads that are part of
their day to day operation.
→→ Industrial refrigeration is a good example of
a building load that can be varied for a short
period of time without too much dependency
period, i.e. during periods of grid constraints.
on external factors. The thermal inertia of the
Current practice
a period without the internal temperature rising
system allows the cooling load to be reduced for
Heating and cooling set point control (with increased
comfort bands)
→→ Can be done via the BMS, or home energy
management systems such as Hive for small scale
residential.
→→ Metering
strategy
may
need
to
account
specifically for heating load.
→→ This increases the comfort band, thus ramping
down mechanical plant for short periods of time.
→→ Heat pump systems often come with control
and metering built-in, so linking with demand
response systems should be straightforward.
→→ Hot water systems with thermal storage often
have more opportunities for active demand
response.
Climate Emergency Design Guide
too much. This has been trialled with some major
supermarkets3.
Distributed alert system
→→ Encourages residents to turn down their energy
use through the use of incentives. For example, a
phone app or text alert system with ‘proof of turn
down’ metering analysis via the smart meter.
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89
Peak Reduction
Future practice
→→ Small power equipment – Has not been observed
to directly participate in flexibility markets as of
→→ Lighting – Reduction of lighting levels in periods of
grid constraints. This is currently rare due to safety
concerns and potential breaching of lighting
regulation, but there have been suggestions of
raising and lowering the brightness of lighting
levels
to
provide
flexibility
within
allowed
tolerances.
→→ Reduction
Electricity Usage
requirements.
Electricity Supply
yet due to the high volume installation/retrofit
Average Day (time)
in
ventilation
requirements
–
Mechanical ventilation to ramp down to achieve
Active demand response measures Thermal Storage
minimum rates for short periods of time.
→→ Voltage/power factor control
→→ Once a development reaches a certain size
response programs.
→→ These work in a similar way to the standard
energy consumption rate reduction seen
in most energy flexibility programs, except
it deals with very local grid constraint
problems.
charge
thermal
store
use thermal
store
Electricity Usage
to ask about voltage control or power factor
Electricity Supply
it may be prudent to consult your local DNO
Average Day (time)
Electricity Supply
Electricity Usage
Electricty Usage with key
demand responce measures
Figure 4.3
- Peak reduction
and active
Increase
User Demand
demand response measures. Visual
representations of the various demand
response solutions discussed in this
chapter.
LETI
alert to turn
down energy
Average Day (time)
Electricity Usage
Key
Electricity Supply
Active demand response measures Distributed alert system
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90
Electricity generation and storage
Electric vehicle (EV) charging
Products that can generate electricity to feed into the
It is generally accepted that while the market
grid, or power the building, reduce demand on the
penetration of EV charging is currently low it will
grid when the grid is constrained:
increase as the number of electric vehicles increases.
In order to ensure grid stability, it will be essential that
Battery systems
demand response initiatives are implemented for
There are several different types of batteries that have
charging loads as the number of EVs grows.
relevance in different applications.
→→ Lead acid – Simple car batteries, they are easy to
dispose of but have poor energy density.
Electric vehicle turn down
→→ Lithium Ion – Higher energy density, used in
This involves charging EVs only when needed and
laptops, mobile phones and now domestic
allowing the supplier to cut the charging short during
battery storage systems. They have high speed
peak times. The users inform the supplier when they
energy delivery. Reconditioned used lithium
need the EV and the minimum charge required. The
batteries taken from electric vehicles when no
electrical supplier then identifies a time for optimal
longer meeting peak performance, are available
charging and electricity use. A third party service
for use in buildings.
provider can offer the flexibility in wholesale or
→→ Flow Batteries – Uses an electrolyte fluid and metal.
ancillary services markets or to the distribution network
The technology is increasingly finding a role at an
operator. It can also be used to manage the peak
industrial scale. The disposal is much easier than
demand of the building or estate, to avoid the cost of
lithium batteries, and safer in operation.
installing a higher capacity network connection.
Solar to hot water heat storage
Vehicle to Grid
Excess solar generated electricity is used to generate
This reverse charging EV technology
heat and stored as hot water. This is usually via an
battery of the EV to be used to supply the building.
immersion heater in a hot water cylinder.
The charge point supplies energy to the building
allows the
during grid peak electricity periods. This is subject to
having sufficient charge in the EV battery. Electricity
from the battery is used behind the meter rather than
using the grid supply.
Climate Emergency Design Guide
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91
Behaviour change
Electricity generation and storage
It may be worth noting that people do not generally
consider the impacts of when they use electricity.
Participating
in
educational
initiatives
to
raise
be a worthwhile endeavour.
Responsive Occupancy
If using a hot desk policy, office workers could be
moved to be in the same parts of the building during
periods of lower occupancy. This would allow the
charge
battery
use battery- excess
feeds into the grid
charge
battery
Electricity Usage
in voluntary schemes to reduce peak demand would
Electricity Supply
awareness and increase enthusiasm for participation
Average Day (time)
heating or cooling to be focussed on the occupied
areas, with the unoccupied areas untreated or at a
setback temperature, saving energy.
Electric vehicle (EV) charging
Microgrids
island’ essentially cutting itself off from National
energy networks if needs arise. This is potentially quite
complicated, but has a large potential to improve
flexibility and reduce demand from the grid locally,
see Figure 4.5.
charge
car battery
use car batteryexcess feeds into
the grid
charge
car battery
Electricity Usage
would allow the development to operate as an ‘energy
Electricity Supply
Being part of a small semi-isolated energy network
Average Day (time)
Behaviour change
Electricity Usage
Electricty Usage with key
demand responce measures
Figure 4.4
- Generation
and storage,
Increase
User Demand
EV charging, and behaviour change
measures. Visual representations of
the various demand response solutions
discussed in this chapter.
LETI
increased
energy
usage
decreased
energy usage
Average Day (time)
increased
energy
usage
Electricity Usage
Electricity Supply
Electricity Supply
Key
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4.4 Implementation
mechanisms (how?)
Whatever the asset type used,
the potential for
In order to drive buildings to be more flexible in energy
breaching other agreements or regulations must be
use and improve their ability to actively reduce their
considered. LETI would advise that you define your
ongoing carbon emissions, LETI proposes the following
planned approach early on in the design process so
policies to be included in building regulations.
that potential clashes can be identified and avoided.
LETI believe that stronger government policy in this
→→ Each building should be required to undertake
area can help to fully realise demand response
an energy flexibility assessment as part of their
opportunities at the design stage. This will allow more
energy statement. This assessment should record
buildings to have and provide the associated carbon
the total kW of energy available that can be
emissions
controlled and how long the demand can be
reduction
and
operational
resilience
benefits.
reduced, or energy stored for on a per building
basis.
→→ Following the implementation of a structured
assessment
process,
LETI
proposes
that
a
minimum requirement should be established for
Microgrids
all new buildings.
charge
share excess
energy
charge
Electricity Usage
Electricity Supply
An example of this requirement could be, the peak
Average Day (time)
load of the building should be capable of being
reduced by 30% within 1 minute for at least 2 hours.
In order to implement demand response measures,
an industry key performance indicator metric needs
to be developed. This allows the energy flexibility of
a development to be set at the design stage. The
design can then be developed to meet the targets
and meeting these targets can be monitored in use.
Key
Electricity Supply
Electricity Usage
Various options for this metric are outlined below:
→→ Aspect ratio – between peak energy consumption
and daily average consumption.
Electricty Usage with key
demand responce measures
→→ How much of the year could the development
Increase User Demand
→→ How much of the energy use could be shifted to
Figure 4.5 - Impact of Microgrids. The operational daily cycle of
energy on a microgrid or heat network
use demand response systems?
a different time?
→→ In times of grid constraints, the development can
reduce peak demands by X kW for X many hours.
→→ The development can run autonomously for X
hours.
Climate Emergency Design Guide
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93
4.5 Case studies
4.6 References
Dudley College’s Centre for
Advanced Building Technologies
(Advanced II)
1
4,400m2
of
further
education
accommodation
including seminar rooms, workshops, BIM training,
offices and associated ancillary space.
Peak demands reduced by enhanced building
envelope
performance,
modest
window
sizes,
together with heating/cooling pipework operating
at ‘Ambient Loop’ temperatures embedded into
room-exposed ceiling and floor slab thermal mass.
These measures are expected to reduce peak energy
demands by some 45%. Central plant capacity
requirements are likewise reduced with heating plant
design capacity of less than 20W/m2. Other measures
include pipework configuration to ensure the variable
speed pumps pressure head is no more than 50kPa.
During the first year the chillers operated for fewer
than 50 hours.
Figure 4.6 - Dudley College’s Centre for Advanced Building
Technologies (Advanced II)
LETI
-
Ofgem,
power
Investigation
outage
[Online]
into
9
Available
August
from:
2019
https://
w w w.ofgem.gov.uk /publ ications- and - updates/
investigation-9-august-2019-power-outage
2 - Wood J, National Grid says it can go 100%
renewables
[Online]
by
Available
2025,
from:
the
energyst
website
https://theenergyst.com/
national-grid-says-can-go-100-renewables-2025/
3 - Grundy A, Tesco trials offering up fridges for
frequency
response,
Available
from:
Current
Website
[Online]
https://www.current-news.co.uk/
news/tesco-trials-offering-up-fridges-for-frequencyresponse
Climate Emergency Design Guide
LETI
5
Data disclosure
95
5
96
Key performance
indicators
1
2
3
4
Ensure total building energy
consumption is metered and recorded
securely and reliably.
Submeter renewables, heating fuel (e.g.
heat pump consumption) and special uses
separately.
Carry out an annual Display Energy
Certificate (DEC) for non-domestic buildings
and include as part of annual reporting.
123
Upload five years of data to GLA and/or
CarbonBuzz online platform.
Metering strategy for commercial offices to follow BBP Better Metering Toolkit guidance.
Climate Emergency Design Guide
5
97
Summary
Client/Developer (decision
making)
→→ Report
against
operational
energy
→→ Post process shared energy data using annual
average carbon factors to provide reliable and
comparable carbon emission information for
targets
following completion.
→→ Include central collection and collation of
sub-metered energy data in the project brief.
→→ Use a central data store and a private online
data platform for collating, presenting and
interrogating building or asset energy data.
→→ Upload aggregated energy data to publicly
available and open source data platform.
→→ Consider a Display Energy Certificate (DEC)
assessment
annually
as
a
reliable
energy
reporting framework.
→→ Specify a breakdown of energy consumption by
use types that are specific and relevant to the
organisation, for example space heating, hot
water and split between landlord and tenants.
This must form the brief for the metering strategy.
Policymaker (strategy)
→→ Provide an open source and public platform for
sharing energy data on all buildings. Collaborate
with authorities and institutions to use existing
resources as a basis for developing a robust and
flexible platform.
LETI
each building. Report on aggregated carbon
emissions from buildings at a local level.
→→ Mandate operational energy ratings and energy
disclosure for new buildings for a period of at
least five years.
→→ Enable and encourage continued reporting of
energy consumption data for existing buildings,
for example through automated reporting.
→→ Review Display Energy Certificate benchmarks
and guidance.
Designer (implementation)
→→ Identify the outcomes that will be monitored and
ensure the metering strategy can achieve this.
→→ Specify, design, commission and document sub
metering to suit the size and use of the building,
to allow identification and diagnosis of problems,
and to give a breakdown of consumption by use
type.
→→ Use a dedicated data store to save energy
consumption information, do not rely on the BMS.
→→ Prepare a building Log Book at handover.
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98
5.0 Introduction
It seems obvious, but reducing the actual carbon
We
emissions arising from a building’s construction and
operational energy consumption is one small part of
operation is what matters. This is what will reduce
post occupancy evaluation and improving buildings,
the construction sector’s impact on our climate. To
but it is an urgent and tangible one. Collecting
measure and report actual carbon emissions and
data on other building metrics such as occupant
drive reduction, we need to measure and report
satisfaction, embodied carbon, water consumption
energy consumption at a far larger scale than
etc.. should be added to any successful mechanism
currently achieved, and to make the process far more
and platform in the future.
acknowledge
that
monitoring
building
simple and transparent.
More than this, we know there is still a performance
buildings better, we need to create or improve the
5.1 Contribution to zero
carbon (why do it?)
feedback loops between buildings in operation and
The absence of reliable, independent, trusted data
design.
on building performance has led to a situation where
gap between the design estimates and operational
energy and carbon emissions of buildings. To make
the performance of, and emissions from, buildings is
There has been a lot of good work in this area, but it
broadly unknown.
is complex and previous efforts have stalled. A fresh,
invigorated and collaborative industry-wide push
Measuring and reporting real energy consumption
is needed to build on what has come before, and
means the actual carbon emissions arising from
help building designers and clients to understand the
buildings can be calculated and verified during
energy use and emissions of buildings. This requires
operation, and the effectiveness of the other
two main actions:
measures described in this guidance evaluated. With
Improving the scale, quality, consistency
and visibility of energy data reported by
building owners and designers.
Improving access to building energy data
and insights through reporting platforms.
This section focuses on the first action and gives
best practice guidance for setting up energy data
collection from a bottom up, building by building
perspective.
Climate Emergency Design Guide
real energy data we can:
→→ assess progress
→→ make building energy consumption visible
→→ improve benchmarking and targets for new
buildings
→→ demonstrate what is possible
→→ share successful interventions
→→ speed up change in the sector.
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5.2 Current Challenges
The construction industry is unanimous in agreement
prevents this valuable information from contributing to
that more feedback and more data would improve
improving performance or allowing designers to learn
building design and reduce carbon emissions, and has
what does or does not work. Schemes like the Better
been for some time. However, attempts to galvanise
Building Partnership (BBP), Real Estate Environmental
1
this into action, like the collaborative CarbonBuzz
Benchmark, CDP, GRESB and BRE’s collected data on
website, have not yet evolved into the tools the industry
BREEAM, could all play a massive part in getting to
needs. The many and disparate data sets that do exist,
zero carbon if they publicised and shared their data.
built up with great investment and intent, often do not
share data or subscribe to open data standards. This
Main challenges for data disclosure from past industry experience
A..C
123
£££
Data is often very
poor quality
This can be due to anything from mistakes in data entry, meter reliability, metering design
issues, and lack of commissioning or setup, to incorrect or out-of-date conversion factors,
confused time periods, undefined responsibility and selective reporting.
Data often lacks
context
Anonymous or poor background information can make data useless for analysis. Common
missing information types are location or setting, basic occupancy information, end use,
presence of any unusual energy intensive activities, and even simple building information
like floor area.
Metering and
collection is not
joined up
There is often no central storage or repository for data, or meters simply are not connected
and metering information is lost. Typically there are meters installed, but what is metered
is often poorly configured, not properly commissioned and how the data is stored is not
resolved.
Buildings are
complex
There are a myriad of building types. This can often lead to confused reporting, for example
not knowing whether energy is reported for a single building or the whole site when one
energy supply covers multiple buildings, or separating landlord and tenant energy use in
a multi-use building. Sub-metering requirements in client briefs or environmental standards
mean there is often a very high level of data resolution, however collating this information
into useful and consistent reporting can be extremely difficult.
It is an additional
cost
Monitoring and post processing data can be expensive or perceived as expensive.
Often proposals are overly complex and focus on what can be metered rather than
what information is needed and what should be reported. For one-off building clients or
developers there is little incentive, or perceived benefit of monitoring and it is seen as
optional.
Privacy or
commercial
interest concerns
prevent sharing
A tension can exist between transparency and privacy or commercial interests. There is an
expectation that the data collected about a building is worth something, and a fear that
it could expose valuable information about a client or organisation. For example landlords
could be wary of being penalised for excessive energy use by tenants. If performance is
poor, data disclosure at a building level is perceived to create a risk to a business (a threat
to yield or asset value).
Figure 5.1 - Challenges for data disclosure
LETI
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100
5.3 Key components/
solutions (what?)
LETI proposes a framework for collecting and reporting
building, however the proposals here should be seen
data which is simple, appropriate to the scale of the
as the minimum requirement and the priority for any
building, and prioritises reporting basic information
data collection infrastructure.
well, rather than complex information badly.
The purpose of data disclosure is transparency and
Data disclosure is about sharing basic but useful
feedback. However, once the principle of disclosure
metered data and context. Consistency is key to
is established it would allow mandatory operational
making useful comparisons. Building owners and
energy standards to be introduced.
designers may decide to go into more detail in order
to optimise or diagnose specific issues with their
Sub-metering
Data storage
Utility meters
Data disclosure
(input by applicant
or automated)
Information from
external sources
Building
performance
monitoring for
diagnosis
Reported publicly
(output)
Web interface
BMS
Reported privately,
useful for facilities
team or occupant
Reported to
organisation/
homeowner/users
Figure 5.2 - The flow of information from building metering to reporting. The difference between data for disclosure, data
that is publicly reported, and data for building diagnosis is shown.
Climate Emergency Design Guide
Quantify real
carbon emissions
from building.
Useful for industry,
designers,
developers,
develop
benchmarks
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How data is reported
In the short term the recommended platform for
The developer should disclose energy data and key
action. Users could consider uploading to the AECB
building context information on a publicly available
and open source data platform for a minimum of five
years. Where consumption data could be sensitive,
buildings/dwelling are aggregated or averaged
rather than anonymised. The data would be in the
public domain and should use an open data license
such as the Open Government Licence or Creative
Commons 4.0 .
2
The responsibility for reporting should lie with the
building developer. This could be passed on to third
parties who would be responsible for reporting back
to the authority and the building/dwelling owner.
It is acknowledged that there are very few policy
mechanisms to penalise developers who do not report.
Nevertheless, softer incentives, consumer interest
and input from building professionals could create a
culture of disclosure that is a vast improvement over
the current situation. Incentives might include public
lists of developers who have not submitted within 14
months, and publicity for schemes that have reported
data.
At present a simplified reporting structure based
on manual input has been described as a way to
implement data disclosure quickly. This should not rule
out development of more automated reporting in the
future. Working towards automated energy reporting
of individual buildings or small geographical areas
would be a step change in feedback. However current
efforts are limited due to potential data security risk,
and the lack of context for meter readings. Metering
and energy companies do not collect information
about the building.
LETI
data disclosure is CarbonBuzz1 to allow immediate
Low Energy Building Database3 as well. However, new
platforms should be adopted as they are developed.
In particular this includes the ‘Be Seen’ reporting
framework for the London Building Stock Model
(LBSM) from The Greater London Authority (GLA), and
new platforms from the RIBA and CIBSE. These new
platforms should ensure that it is possible to share
building information between databases to avoid
duplicating input. The LBSM will have the capacity to
capture energy performance targets (e.g. predicted
DEC ratings for non-residential buildings) for major
new developments in London and to show if these
are achieved when operational data becomes
available, fulfilling the ‘Be Seen’ element in the new
(2020) London Plan.
It is hoped that by creating a culture of robust data
collection and disclosure, and increasing the amount
of building information available, there will be more
interest and a larger incentive to improve the tools for
sharing and interrogating that data. If we collect it,
then they will want to use it.
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What data should be reported?
All the information listed should be brought together
Data should be reported for the whole building,
made public.
but complex buildings can separate reporting by
use category, for example to differentiate between
residential and commercial, and landlord and tenant.
Annual energy consumption by fuel type and annual
energy generation is required, along with some
contextual information about the building. The data
should be reported for a minimum of five years. The
reporting platform is likely to allow further voluntary
input, so this guidance gives the minimum required for
and uploaded, however not all this data would be
The developer would have final responsibility for
energy disclosure, but they could identify a person
responsible for reporting to pass on the management
of this. This could be a continuing lightweight
appointment for part of the design team, a specialist
service, or taken on by the building owner or energy
manager.
robust net zero carbon reporting.
Information to be reported
ABC
Property
information
→→
→→
→→
→→
→→
→→
→→
Address including postcode
Completion date of building
Building regulations Part L version used
Number of dwellings
Total floor area OR Total useable floor area and the definition used for calculation
Building description and photo
For Display Energy Certificates (DEC)s:
→→ Date of assessment OR Issue date
→→ Certificate reference number
Building
categorisation
→→ DEC Category(s) OR Residential use category(s)
→→ Gross internal floor area for each use (from DEC Full Technical Table)
→→ Single defined building OR Number of buildings
Energy
consumption
→→
→→
→→
→→
→→
Heat
consumption
→→ Only required for projects on district heating, optional for others
→→ Metered heat consumption for building (kWh)
→→ Heat network provider* (Carbon factor will be supplied by the heat network
provider)
Energy
generation
→→ Provided over a bespoke date range and normalised to year by platform, split
between PV and other
→→ Metered electricity generation (kWh)
Carbon offset
→→ Annual CO2 emissions that are offset (displaced emissions)*
Provided over a bespoke date range and normalised to year by platform
Metered electricity consumption (kWh)
Metered gas consumption** (kWh)
Other fuel consumption** (kWh)
Data source quality
*Not currently possible to input to CarbonBuzz, but should be recorded in notes.
**Other fuel and heat consumption are combined into one output on DECs
Figure 5.3 - Suggested information to be reported for data disclosure
5
103
The platform calculates carbon emissions and other
reported metrics (e.g. total kWh/m2 consumption).
This means that the carbon factors and calculation
method are consistent. CarbonBuzz uses out-of-date
carbon factors and so cannot currently be used to
report, however this can be updated retrospectively
For non-domestic buildings an annual Display Energy
Certificate is sufficient to satisfy the majority of inputs.
The assessment is carried out by a competent person
and has the advantage of quality assurance on data
input. The Full Technical Table should be requested
from the assessor to assist with input.
and would be a key part of any new platform.
A
A new
new data
data platform
platform
CarbonBuzz is now an old platform and has
more or less fallen out of use (only two projects
were uploaded in 2018). It is cited here as the
best operational platform for collecting building
data available. However, it is dated, complex
and presents a further barrier to uploading
energy
performance
data.
Improvements
to
the CarbonBuzz platform, or a new platform are
needed. The RIBA and CIBSE are considering
delivering new data platforms in 2020. The GLA
and UCL are working on a London Building Stock
Model (LBSM) that would allow reporting of energy
consumption. LETI fully support these initiatives and
hope that it can be part of a collaborative industry
and Government effort to provide national building
amount possible, see the LETI GLA energy
disclosure flow diagram in Appendix 5.1.
→→ Ensure data upload and access can be
automated
including
a
through
other
web
accessible
platforms
by
Application
Programming Interface (API).
→→ Check information as it is inputted and provide
feedback to catch mistakes. For example,
warning messages where data is very different
to that submitted previously for the same
building or for other similar buildings in the
dataset.
→→ Report each year of carbon emissions with the
average annual grid carbon factor to give
estimated carbon emissions.
statistics.
→→ Provide simple email messaging to remind
LETI recommends that any new platform should:
→→ Encourage and allow voluntary upload of
→→ Migrate the existing data from CarbonBuzz
and allow other databases to import or export
information, for example from the AECB Low
Energy Building Database.
→→ Make raw source data available to the public
for research through open source licensing.
→→ Simplify the reported information to the least
users about reporting due dates.
energy consumption of existing buildings.
→→ Encourage voluntary sharing of further detail,
such
as:
breakdown
of
consumption
by
end-use, by landlord areas/ tenants and any
unusual energy intensive activities.
SIGNPOST Appendix 5 - Data disclosure
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104
What data is made public?
the technical details are necessary for designers
Future platforms should publish open data for
housing, aggregation of data across dwellings on the
transparency, analysis and research purposes. The
platform should post process and give options for
aggregation so that the exact building and user could
be hidden. However, the user should be able to, and
and building professionals to diagnose actions. For
same street could be used.
How data should be collected?
be encouraged to, publish all information voluntarily
At its most basic, data collection could be manual
if they wished. The energy data is aggregated to
input from utility meter readings reporting consumption
annual consumption and would be published at
in kWh for a given period. However, for most buildings
least two months after the reporting data to reduce
some level of automated metering and data logging
the sensitivity. Public reporting could use consumer
is likely to be useful. How this is implemented is crucial
friendly metrics, such as star or A-G ratings. However
to the reliability of readings.
The following information should be published by the platform
ABC
CO2
123
Property
information
→→
→→
→→
→→
→→
→→
Building
categorisation
→→ DEC Category(s) OR Residential use category(s)
→→ Gross internal floor area for each category
→→ Data source quality
Carbon
emissions
Energy
Postcode or part of the postcode (e.g. first four digits)
Completion date of building(s)
Building regulations Part L version used
Total floor area OR Total useable floor area and the definition used for calculation
Number of buildings
Number of dwellings (may be aggregated between buildings)
→→ Total annual CO2e emissions from building (kgCO2e/m2)*
→→ Total net CO2e emissions from building (kgCO2e/m2)*
→→ Total annual CO2e emissions (kgCO2e)*
→→
→→
→→
→→
→→
→→
→→
→→
For each year reported, normalised to whole year
Total annual energy consumption kWh/m2
Total annual primary energy kWhe/m2
Estimated annual energy cost per residential unit (£p.a.)
Metered electricity consumption (kWh)
Metered gas consumption** (kWh)
Other fuel consumption** (kWh)
Metered electricity generation (kWh)
*See appendix 5 for proposed reporting structure for details
**Other fuel and heat consumption are combined into one output on DECs
Figure 5.4 - Suggested information to be published on a reporting platform
SIGNPOST Appendix 5 - Data Disclosure
Climate Emergency Design Guide
5
105
Data should be quality assured prior to submission
and the nature of the assurance process should
be reported alongside energy disclosure. For small
schemes this might include self-verification against
utility bills, but for larger buildings should include third
party verification or independent certification.
Display
Energy
Certificates
(DEC)
are
for non-domestic buildings. In addition to the DEC
there should be separate optional reporting for energy
use that is the responsibility of landlords (basebuild
ratings), tenants (tenant ratings) and special areas
such as data centres. The DEC methodology and
reporting should be reviewed and changes to the
reporting scale considered to allow future continuous
improvement.
Where a building is occupied by several tenants,
a requirement to make energy data available for
aggregated reporting should form part of the tenancy
lease agreement.
Annual energy data is likely to be collected as a
small part of more complex energy sub-metering.
The design of the system must allow for annual data
collection, for example by including sufficient storage,
and cumulative readings. Data should be collated
at least once per year. Annual energy consumption
is a useful metric to report to the building owner,
organisation, tenants, board or shareholders etc..
In time, providers of energy monitoring services
should be able to report directly to the public energy
disclosure platform via an API. For example smart
meter providers could provide aggregated statistics
for small geographical areas. This would require a
connection between meter readings and building
LETI
Building designers and developers should start
compiling energy monitoring data and reporting
information straight away. There is already a huge
data gap in reporting actual energy use from
buildings, we cannot delay further.
the
recommended approach for collating energy data
context to be established.
Zero carbon trajectory
All new projects should include a metering strategy
and central repository to ensure future public energy
disclosure is simple to implement. Projects can upload
complete information to CarbonBuzz as a stop gap
before an improved publicly accessible platform
is developed. Existing buildings can also focus on
recording and reporting annual energy consumption
data in line with these recommendations.
By 2022 all new buildings should be reporting energy
data publicly. This reporting will be useful in ensuring
the aims of other sections have been addressed, for
example working to close the performance gap,
quantifying actual operational carbon emissions,
providing consumers with information to drive retrofit,
and understanding further benefits such as reducing
fuel poverty.
5
106
Summary of recommendations for each archetype
Small scale residential
Good practice
Medium scale residential
123
Large scale residential
123
123
Best practice
→→ Use a smart meter for continuous monitoring.
→→ Include a power socket near the consumer
unit and utility meters to power data logging
equipment.
→→ Provide a visual energy display device to
raise awareness and make users responsible
for their energy consumption.
→→ Renewables are sub-metered for generation.
→→ Special uses such as electric vehicle
charging is sub-metered.
→→ Separate standalone monitor and data
logger alongside smart meter, or process to
collect data.
→→ Heat supply is sub-metered (e.g. heat pump
electrical consumption).
→→ Internal temperature monitoring.
→→ Annual building energy consumption and
generation is collected by owner reporting,
can be aggregated and averaged by post
code for anonymity.
→→ Upload data to publicly accessible
database for five years.
→→ Additional meter on the main resident’s
supply (or residents meter readings need to
be collected and collated individually).
→→ Renewables are sub-metered for generation.
→→ Special uses such as electric vehicle
charging is sub-metered.
→→ If there is a heat network use individual heat
meters per dwelling.
→→ Provide a visual energy display device to
raise awareness and make users responsible
for their energy consumption.
→→ Meter and report landlord areas separately.
→→ Sub-meter heating energy by dwelling.
→→ If there are commercial areas meter and
report these separately.
→→ Ensure OFGEM compliant meters.
→→ Upload data to publicly accessible platform
for five years.
→→ Annual energy consumption per dwelling
reported (without address).
→→ Report heating energy consumption.
→→ Additional meter on the main resident’s
supply per building (or residents meter
readings need to be collected and collated
individually).
→→ Renewables are sub-metered for generation
per building.
→→ Special uses such as electric vehicle
charging is sub-metered.
→→ If there is a heat network use individual heat
meters per dwelling.
→→ Provide a visual energy display device to
raise awareness and make users responsible
for their energy consumption.
→→ Meter and report landlord areas separately.
→→ Sub-meter heating energy.
→→ If there are commercial areas meter and
report these separately.
→→ Ensure meters are OFGEM compliant.
→→ Upload data to publicly accessible platform
for five years.
→→ Annual energy consumption per dwelling
reported (without address).
→→ Report heating energy consumption.
Climate Emergency Design Guide
Commercial office
5
107
School
123
123
Good practice
Best practice
→→ Metering strategy following BBP Better
Metering Toolkit guidance. This includes:
→→ Using a central repository for data that
has a minimum of 18 months data
storage.
→→ Clearly labelled meters, good
documentation and schematics - serial
number and usage.
→→ Sub-meter tenant and landlord area energy
use separately.
→→ Sub-meter renewable energy generation.
→→ Ensure meters can provide consumption by
end use with minimum breakdown:
→→ Heating and cooling
→→ Ventilation
→→ Domestic hot water
→→ Lighting
→→ Small power
→→ Servers
→→ Pumping
→→ Lifts + escalators
→→ Catering
→→ Special uses e.g. server rooms
→→ Carry out an annual DEC.
→→ Report energy consumption by building
category from DEC technical table. For
multi-let commercial offices produce annual
landlord energy (base building) rating and
tenant ratings as well as or instead of a
whole building DEC.
→→ Upload data to publicly accessible platform
for five years.
→→ Report consumption by end use per
building.
→→ Report special uses separately.
→→ Require reporting of base building and
whole building “base load” (out of hours)
electricity demand (W/m2), and proportion
→→ Metering strategy following BBP Better
Metering Toolkit guidance. This includes:
→→ Using a central repository for data
that has a minimum of 18 months data
storage.
→→ Recording at a minimum of half hourly
time steps.
→→ Clearly labelled meters - serial number
and usage.
→→ Good documentation – schematics
with meters and end use.
→→ Maintenance and use strategy.
→→ Sub-meter renewable energy
generation.
→→ Ensure meters can provide consumption by
end use with minimum breakdown.
→→ Heating and cooling
→→ Ventilation
→→ Domestic hot water
→→ Lighting
→→ Small power
→→ Servers
→→ Pumping
→→ Lifts
→→ Catering
→→ Special areas and uses (e.g. labs and
swimming pools)
→→ Carry out an annual DEC.
→→ Upload data to publicly accessible platform
for five years. Include information about
building (do not anonymise).
→→ Report consumption by end use per
building.
→→ Report special uses separately.
(%) and amount (kWh/m2.yr) of whole
building annual electricity use that occurs
out of hours (outside core and shoulder
hours of use).
Key
Metering
Figure 5.5 - Summary of recommendations by archetype
LETI
123
Disclosure
5
108
5.4 Implementation
mechanisms (how?)
5.5 Case Studies
To enable a reporting system to work, a robust reporting
platform is required that provides a simple and reliable
method for organisations to provide and extract
useful data. LETI has included recommendations on
Boston energy map
The Boston building energy reporting and disclosure
ordinance4 requires Boston’s large and medium sized
what this platform should include.
buildings to report their annual energy and water
To kick start energy disclosure to this platform the
energy savings action or energy assessment every five
use. It further requires buildings to complete a major
Greater London Authority (GLA) are planning to
mandate energy disclosure for major planning
applications (>10 dwellings, >1000m2). This should be
years. The Boston energy map5 gives building level
greenhouse gas emissions along with information
about the building and its user.
extended to all non-domestic buildings as a further
step. It is also crucial that existing buildings that wish
to use the system are encouraged and incentivised
to do so.
Once a significant amount of information is publicly
available and usable, building owners and occupiers
may begin to see the value in reporting and using
this data to inform their business decisions. Levels of
awareness could be raised and maintained through
public
recognition
of
reporting
organisations,
validation within industry benchmarking services
such as Carbon Disclosure Project (CDP), Global Real
Estate Sustainability Benchmark (GRESB), Chartered
Institution of Building Services Engineers (CIBSE), and
even through the use reporting as a consideration
within the property policies of public sector bodies
and other major occupiers.
Energence automated energy
monitoring platform
Since 2013 Ealing Council have required all applicants
or
developers
submitting
major
development
proposals to planning to undertake monitoring postconstruction to demonstrate compliance with the
energy policies of the Local Plan. Ealing Council
worked with Energence to create an Automated
Energy Monitoring Platform (AEMP) so that developers
can upload information that is checked with minimum
input. They can pay up front subscription costs to the
scheme through their Section 106 payments, meaning
no further input is required. The data does not appear
to be available publicly and is not an open source. It is
not known how successful this scheme has been.
Australian NABERS scheme
The National Australian Built Environment Rating System
(NABERS) is an operational reporting benchmark
which has significantly disrupted the market for
commercial buildings by creating a demand for
buildings with lower energy consumption. It has
demonstrated continuous reduction in operational
energy consumption since it’s introduction.
Climate Emergency Design Guide
5
109
ing used?
Certificate Reference Number:
0591-0111-2189-9091-1002
5.6 References
A NABERS type scheme is being introduced to the UK
1- CarbonBuzz [Online]. Available from: http://www.
by the BBP, see Design for Performance6.
carbonbuzz.org/
lding. The operational
is baseddisclose
on meter readings
of all
NABERS rating
publicly
operational
energy
ng, ventilation and hot water. It is compared to a benchmark that
performance of buildings using the scheme. ‘Nabers
e advice on how to interpret this information in the guidance
7
’ is awebsite
usefulat:example showing how
by the
numbers
ngs available on
Government's
the open source data has been used to create
2 - Creative Commons [Online]. Available from: https://
visualisations and call out individual building owners
Available from: http://www.lowenergybuildings.org.
ers do
nergy
Total
CO2 Emissions
on energy
consumption.
This tells you how much carbon dioxide the
building emits. It shows tonnes per year of
CO2.
Disclosure:
uk/
4 - City of Boston, Building Energy Reporting and
Transport for London’s Palestra building achieved
https://www.boston.gov/departments/environment/
an initial Display Energy Certificate rating of G(182)
building-energy-reporting-and-disclosure-ordinance
Disclosure Ordinance [Online]. Available from:
when first commissioned in 2010. Through building
performance evaluation and careful monitoring the
5 - City of Boston, Boston Energy Map
rating was reduced to a DEC of D(93) in 2019. This
[Online]. Available from: http://boston.maps.
demonstrates how high-level reporting of building
arcgis.com/apps/webappviewer/index.
energy consumption can incentivise organisational
html?id=b3ea9b33314541c6a2663732698fd92a
change and deliver real carbon emission savings.
6 - Better Buildings Partnership, Design
Performance [Online]. Available from: http://www.
Previous Operational Ratings
This tells you how efficiently energy has
been used in this building over the last three
accounting periods.
betterbuildingspartnership.co.uk/our-priorities/
measuring-reporting/design-performance
7 - NABERS, NABERS by Numbers [Online].
Available from: https://public.tableau.com/profile/
richardstokes88#!/vizhome/NABERSbyNumbersv2/
NABERSbyNumbers
back to 2010.
ay Energy Certificate as defined in the Energy Performance of Buildings
012 as amended.
e:
3 - AECB Low Energy Buildings Database [Online].
TFL Palestra building
Figure 5.6 – Extract from the DEC certificate for Palestra
ative Information
building in 2019 showing three previous energy ratings
oftware:
ence:
e:
ber:
Scheme:
ing Name:
ing Address:
creativecommons.org/licenses/by/4.0/
LE
SystemsLink, ORToolkit, v3.6
998111020001
Quinten James Babcock CEng MCIBSE
LCEA027066
CIBSE Certification Limited
Transport for London
6th Floor East Wing, 55 Broadway, London, SW1H
T0BD
I
17-10-2019
30-09-2019
29-09-2020
Employed by the occupier.
Climate Emergency Design Guide
LETI
A
Appendix
111
Appendix 0
112
A0.1: Net zero operational carbon
Net Zero Operational Carbon
Ten key requirements for new buildings
By 2030 all new buildings must operate at net zero to meet our climate change targets. This means that by 2025 all new
buildings will need to be designed to meet these targets. This page sets out the approach to operational carbon that
will be necessary to deliver zero carbon buildings. For more information about any of these requirements and how to
meet them, please refer to the: UKGBC - Net Zero Carbon Buildings Framework; BBP - Design for Performance initiative;
RIBA - 2030 Climate Challenge; GHA - Net Zero Housing Project Map; CIBSE - Climate Action Plan; and, LETI - Climate
Emergency Design Guide.
Low energy use
Annual energy use and renewable energy
generation on-site must be reported and
independently verified in-use each year
for the first 5 years. This can be done on
an aggregated and anonymised basis for
residential buildings.
Lo
rs
Em
bodie carbon
d
Reducing construction impacts
4
Embodied carbon should be assessed,
reduced and verified post-construction.3
Developed in collaboration with:
L ONDON
E NERGY
T RANSFORMATION
I NITIATIVE
Lo w c
arb
on
5y
3
e
Measurement and verifcation
me
e
ur
as
Building fabric is very important therefore
space heating demand should be less than
15 kWh/m2/yr for all building types.
use
y
2 yr
rg
/m /
e
h
kW
en
Net Zero
Operational
Carbon
verifcation
2
nd
nt a
For non-domestic buildings a minimum
DEC B (40) rating should be achieved and/or
an EUI equal or less than:
• 65 kWh/m2/yr (GIA) for schools1
• 70 kWh/m2/yr (NLA) or 55 kWh/m2/yr (GIA)
for commercial offices1,2
w
Total Energy Use Intensity (EUI) - Energy use
measured at the meter should be equal to or
less than:
• 35 kWh/m2/yr (GIA) for residential1
M
1
Developed with the support of:
Appendix 0
113
Low carbon energy supply
n
Heating and hot water should not be
generated using fossil fuels.
6
The average annual carbon content of
the heat supplied (gCO2/kWh) should
be reported.
7
On-site renewable electricity should be
maximised.
8
Energy demand response and storage
measures should be incorporated
and the building annual peak energy
demand should be reported.
ly
pp
su
5
Zero carbon balance
Z
e
r
o
c
arb
o
nb
ala
n
ce
9
A carbon balance calculation (on an
annual basis) should be undertaken
and it should be demonstrated that the
building achieves a net zero carbon
balance.
10
Any energy use not met by on-site
renewables should be met by an
investment into additional renewable
energy capacity off-site OR a minimum
15 year renewable energy power
purchase agreement (PPA). A green
tariff is not robust enough and does not
provide ‘additional’ renewables.
Notes:
Note 1 – Energy use intensity (EUI) targets
The above targets include all energy uses in the
building (regulated and unregulated) as measured at
the meter and exclude on-site generation. They have
been derived from: predicted energy use modelling
for best practice; a review of the best performing
buildings in the UK; and a preliminary assessment of
the renewable energy supply for UK buildings. They
are likely to be revised as more knowledge is available
in these three fields. As heating and hot water is not
generated by fossil fuels, this assumes an all electric
building until other zero carbon fuels exist, (kWh targets
are the same as kWhelec-eq). Once other zero carbon
heating fuels are available this metric will be adapted.
Note 2 – Commercial offces
With a typical net to gross ratio, 70 kWh/m2 NLA/yr is equivalent
to 55 kWh/m2 GIA/yr. Building owners and developers are
recommended to target a base building rating of 6 stars using
the BBP’s Design for Performance process based on NABERS.
Note 3 – Whole life carbon
It is recognised that operational emissions represent only one
aspect of net zero carbon in new buildings. Reducing whole
life carbon is crucial and will be covered in separate guidance.
Note 4 – Adaptation to climate change
Net zero carbon buildings should also be adapted to climate
change. It is essential that the risk of overheating is managed
and that cooling is minimised.
Figure A0.1 - Net zero operational carbon
one pager available for download from:
https://www.leti.london/one-pager
Appendix 0
114
A0.2: Actions by RIBA Stage
Operational carbon, future of heat, demand response and data disclosure
1. Identify a net zero
carbon champion.
2. Identify project team
responsibilities to achieve
operational energy use
targets including the
calculation of operational
targets, documenting
assumptions behind
these, managing risks
and validating in-use
performance.
3. Consider contractual
incentives for achievement
of performance targets.
4.Identify a project team
member who can advise
on demand response.
1. Set clear intent for
zero carbon targets
and defi ne what this
includes, document
boundaries and targets.
1. Establish clear energy
use targets, document
targets and strategies to
achieve this and share
with all stakeholders.
2. Set an energy use
intensity target and
embed within the brief
2. Develop the concept
design in accordance with
critical design parameter
recommendations in
this guide. Specific
aspects to consider at
this stage include:
→ Building orientation
→ Building form factor
→ Facade glazing ratio
→ Likely occupancy
patterns
and
operating scenarios
→ Facade glazing ratio
3. Discuss localised energy
constraint issues with DNO.
4. Identify likely eligible
demand response
programmes at a national
and regional scale.
5. Incorporation of
data disclosure into
BIM requirements.
→
Technical systems
integration.
3.Develop a preliminary
operational energy model
aligned to the Energy Use
Intensity targets. Use this
model to guide design
throughout RIBA 2
4. Use the LETI Future
of Heat Decision Tree
when making decisions
on heating and hot
water systems.
5. Implement the most
significant carbon/energy
reduction measures in
design including demand
response and energy
storage opportunities.
6. Highlight the roles
and opportunities for
overcoming performance
gap, for example by
following the BSRIA Soft
Landings Framework.
1. Refi ne a full operational
energy model for evaluation
of predicted energy
demand. Ensure this
simulation goes beyond
regulated energy and
considers energy use from
all items in the building.
2. Test proposed design
changes using the
energy model.
3. Update and document
detailed targets and
strategies to achieve these.
Include design measures
and assumptions of likely
occupancy patterns
and operating scenarios
as well as strategies for
long term adaptability.
4. Ensure proposed
construction details are
robust to support low
energy and airtightness
performance characteristics.
5. Ensure that the risk of
overheating has been
assessed and mitigated.
6. Develop demand
response strategy and
simulate potential impact.
7. Develop sub-metering
strategy using LETI energy
disclosure guidance.
Heating and cooling
energy consumption
(kWh) should be metered
separately to enable fabric
performance to be assessed.
8. Establish a secure remote
source for metered data
to be transmitted over a
communications network for
aggregation and storage.
Appendix 0
115
1. Update building energy
model with latest design
amendments, and ensure
that operational energy
targets are still being
achieved. Document
detailed targets and
strategies to achieve
these targets e.g. by
creating a Building
Performance Register.
2. Confi rm envelope
specification and complete
detail design, ensuring
good continuity of insulation
and airtightness.
3. Check the suitability of
the heating and hot water
system using the LETI Future of
Heat Decision Tree. Confi rm
HVAC systems type and
performance specification.
4. Iterate demand response
model with exact design data
to gain a more accurate
prediction of carbon savings
and monetary gains. Ensure
that specified equipment
can integrate fully to carry
out demand response
processes and events easily.
5. Ensure specified
metering is incorporated.
6. Include operational energy
targets in the construction
tender package, e.g. using a
Design for Performance type
of target and feedback loop.
7. Incorporate in contractors’
prelims with guarantees
to recalculate energy
model if items in the
register are changed
or value engineered, to
demonstrate that ‘as built’
project meets agreed
operational targets. Create
risk register and confi rm
responsibility for managing
this during construction
and commissioning.
1. Where possible, ensure
the appointment of a clerk
of works is responsible
for quality checks.
2. Update energy model
to account for any
changes in the design
or assumptions behind it
and reject substitutions
and omissions if achieving
performance targets
may be compromised
by the changes.
3. Engage with the
supply chain regarding
the design targets of the
project and where possible
provide toolbox talks to
help upskill contractors
and to communicate
the importance of
quality construction.
4. Ensure the contractors
understand commissioning
requirements, including
metering commissioning
and validation of manual
vs half hourly readings.
5. Ensure the contractor
has quality monitoring
processes in place to
ensure proper installation
of insulation, airtightness
layer and mechanical
equipment for the whole of
the construction period.
6. Carry out benchmark
inspections to clarify quality
expectations and continue
to monitor construction
quality, including in-situ
thermal performance
tests, thermographic and
air tightness testing.
7. Ensure the contractor
understands the
commissioning
requirements.
1. Review fi nal construction
including rectification work,
for quality, including in-situ
thermal performance
tests, thermographic and
air tightness testing.
2. Finalise as-built energy
model to account for any
changes in the design or
assumptions behind it.
3. Ensure commissioning
and testing is fully
completed and
witnessed and that the
‘as installed’ controls
strategies, setpoints,
commissioned fl ow rates,
metering etc. are in line
with the energy model.
4. Ensure the building user
is trained and understands
use of the building systems.
5. Ensure that planned
demand response activities
occur correctly as part of
the commissioning process
and that the initial setup
parameters are recorded.
6. Ensure a suitably
qualified individual
understands the energy
management and
measurement systems.
For further information
regarding role and
duties, refer to BBP better
metering toolkit.
7. Ensure that performance
data from sensors and
meters are reconciled
with main meter, spot
meter and BMS readings
and that logs are set
up in BMS to facilitate
long term monitoring of
building performance.
1. For the fi rst year of
occupation both the
building and the targets
should be tuned to actual
building usage patterns.
Ensure a dual focus of
improving accuracy of
targets as well as improving
building operation.
2. Ensure hourly energy
consumption trends
match operating hours.
3. Ensure the metering
system is operating
correctly and is
regularly validated
against utility meters.
4. Identify and track key
efficiency metrics. Aim
to track the fewest but
most useful metrics.
5. Assign an annual budget
for monitoring energy use
and tuning controls in
response. Aim for monthly
review and quarterly
‘deep dive’ analysis.
6. Line up energy efficiency
assessments with post
occupancy evaluation
assessments to ensure
occupant satisfaction with
conditions in the building.
7. Upload total energy
and heating energy
consumption data to a
public data platform for fi rst
5 years post-completion.
Appendix 0
116
The RIBA Stages 1-5 ‘For LCA Specialists’ contents were extracted from the call out box ‘Embodied
and whole life carbon considerations through RIBA Plan of Works’ with some amendments
made by FARNETANI, Mirko. CIRIA Briefing - Whole-life carbon reduction strategy: good practice
methodology. January 2017. Available from: https://www.ciria.org/ [Accessed 25 April 2019] .
Embodied carbon - for the designer
1. Discuss whole life carbon
ambitions with client.
2. Review opportunity
for retention of existing
structure and building
fabric and how the
quantum of materials of the
new build can be reduced.
1. Client brief to be
developed: it should
incorporate embodied
carbon reduction targets.
1. Use rules of thumb
guidance during concept
to maximise opportunities
for low carbon design.
2. Appoint a LCA specialist
or design team member to
be responsible for whole
life carbon assessment.
2. Analyse carbon
reduction options for
building elements using
numerical analysis.
1. Include requirements
and targets for whole life
carbon in specifications
and tender documentation
at start of procurement.
2. Have discussions with the
potential contractors and
subcontractors around whole
life carbon targets, asking for
options for improvement and
including carbon questions
on tender return forms.
3. Continue numerical
analysis and use material
guides to optimise
material specification.
Embodied carbon - for the Life Cycle Assessment (LCA) specialist
1. Set initial embodied
carbon targets using
rule of thumb guidance
and benchmarks.
improvement
Magnitude of
OUTCOMES: Early
recommendations on
low carbon options
ahead of RIBA Stage 2.
Set aspirations
Project brief
1. As the design develops,
provide more detailed
analysis of the options
around the key building
systems: frame, fl oors,
envelope. This is discussed
with the design team
through workshops.
OUTCOMES: More
detailed analysis and
recommendations of the
agreed design options.
Improved understanding of
embodied and whole life
carbon within design team.
Material and product
specification
1. In depth analysis of the
elemental and component
parts of the entire building,
identifying specific materials,
products and lifespans,
to generate a whole life
carbon budget baseline.
2. Assess low carbon
alternatives to the
baseline. Agree a carbon
reduction target - either
percentage or absolute.
OUTCOMES: A whole life
carbon budget, representing
the total carbon emitted
over the lifetime of the
building, and an associated
carbon reduction target.
Initial carbon reduction
option list, which will be
further developed during
technical design stage.
Product and material
efficiency
Appendix 0
117
SIGNPOST Embodied Carbon Primer
1. Finalise requirements
and targets for whole life
carbon in specifications
and tender documentation
at start of procurement.
2. Finalise requirements with
the potential contractors and
subcontractors around whole
life carbon targets, asking for
options for improvement and
including carbon questions
on tender return forms.
3. Continue numerical
analysis and use material
guides to optimise
material specification.
1. Update whole life carbon
budget to include design
development and fi nalise the
carbon reduction options list.
2. Send pre-procurement
Request for Information (RFI)
to suppliers to collect carbon
data in order to provide
supplementary information
for supplier selection. Review
returned RFIs and analyse the
environmental credentials
of procurement options.
OUTCOMES: Agree carbon
reduction targets and carbon
reduction options list in order
to infl uence specifications.
A list of recommended
low-carbon supplier.
1. Engage with contractors
to reduce waste.
2. Review alternative
products and materials
selections proposed
by the contractor
against technical and
performance standards
and against the whole life
carbon requirements.
1. Undertake post
completion analysis
using as-built information
to assess upfront
embodied carbon.
1. Recommendations
regarding embodied
carbon reduction strategy
over the in-use stage
should be followed
throughout the building
life cycle including at
the end of life stage.
1. At the end of site works,
the contractor should
confi rm the final carbon
related data to the LCA
specialist. Develop the
practical completion
carbon report. Align the
design stage carbon
targets with what was
achieved at the end
of construction.
1. Embodied carbon
reduction strategy to
include in-use and
end of life stages.
3. Prepare for postcompletion analysis by
collecting numerical
data through the
construction phase.
1. Send RFIs to suppliers
in order to receive
construction carbon
data and verify the
environmental credentials.
2. Undertake building site
monitoring through monthly
site logs and construction
progress reporting.
OUTCOMES: Facilitate
gathering of data for the
construction stage analysis
and achieve the agreed
carbon reduction targets.
OUTCOMES: Client to
have relevant information
to continue embodied
carbon reduction strategy
throughout in-use and
end of life stages.
OUTCOMES: Practical
completion carbon report
to be issued to the client.
Assess design against
embodied carbon targets.
Ensure specifications
include embodied carbon
of materials. Recommend
a list of suitable low
carbon suppliers.
Material and product
declaration
Material and product
verification
As build carbon report
to client
In-use carbon
report to client
Appendix 1
118
A1.1: ‘Top-down’
Calculations
Methodology: ‘Top-down’
calculations
and retail buildings across England and Wales.
If we are to achieve net zero carbon across the
Scottish Economy4. It is understood that the
Indicative areas for Scottish floorspace were
taken
building stock, the Energy Use Intensity (EUI) for every
building must not exceed the proportion of zero
carbon energy available. LETI has taken the 2030 and
2050 forecasts for renewable energy generation in
Great Britain, and broken down the proportion of that
energy which might reasonably be made available
to buildings. This results in a target or ‘budget’ EUI for
the main archetypes, namely domestic, office, retail
and industrial. Note, all calculations are indicative
and should be refined in future. The approach and
data sources used for calculations are outlined in
further detail below.
→→ Forecast
of
total
from
Commercial
Real
Estate
and
Scottish Government does not keep statistics on
floorspace. An updated estimate for Scotland
would be useful for improving the accuracy of
the ‘top-down’ modelling.
An estimate for the number of domestic dwellings
in Great Britain was found by comparing the Office
for National Statistics’ Families and Households
dataset5 to the Northern Ireland Housing Statistics
2017-186. Total domestic floor area in Great Britain
was then estimated by multiplying the number of
dwellings by the average useable floor area for
properties in England, from the England Housing
Survey Headline Report 2017-187.
renewable
generation
–
National Grid’s 2018 Community Renewables
Future Energy Scenario was used to estimate
1
the amount of renewable capacity, in TWh, that
would be available to Great Britain in 2030 and
2050.
→→ Total energy consumption per building use type
– Data tables of Energy Consumption in the UK 2
provided final energy consumption figures, in
ktoe, per building use type. This was used to
establish the percentage of energy that was
consumed per building use type. This percentage
dictates the amount of future renewable energy
generation that would be assigned to each
building use type, assuming that the split of
office, residential, industrial and other building
types across the UK remains constant.
→→ Total building areas – Non-domestic rating:
Business Floorspace tables provided information
3
on the total floorspace (in m2) for office, industrial
Climate Emergency Design Guide
→→ Forecast building areas – Estimates for the total
domestic floor area in 2030 and 2050 were
calculated by assuming a 1% increase in new
build completion per year.
From analysing trends in non-domestic floorspace
using the Valuation Office Agency’s data tables8
the total floor area for office, industrial and retail
buildings was assumed to remain reasonably
constant and thus the total floor area for 2030
and 2050 would be approximated by 2018 values.
Using the above information, available renewable
generation per m2 for domestic, industrial, office and
retail in 2030 and 2050 was calculated.
Effectively this results in a target EUI figure for domestic,
industrial, office and retail buildings that could
be compared with the results of the ‘bottom-up’
calculations.
Appendix 1
119
Top down modelling
results
Community renewables scenario
available generation - 2030
(kWh/m2 .yr)*
Building type
Renewable
energy only
Renewable
energy plus
nuclear
Community renewables
scenario available generation
- 2050 (kWh/m2 .yr)*
Renewable
energy only
Renewable
energy plus
nuclear
Domestic
27
29
37
43
Industrial (without processes)
27
30
38
44
Office
62
67
85
99
Retail
49
53
67
79
(Renewable energy generation allocated to use type (kWh))/
(Forecast total floor area of building use type (m²))
* area is NIA
Note: Community renewables is the most optimistic of the FESs with regards to forecast renewable capacity by 2050.
For renewable plus nuclear, only the Two Degrees scenario forecasts more capacity than community renewables
(by 5TWh).
Figure A1.1 - Top down modelling results
LETI
Appendix 1
120
UK Green Building Council - ‘Paris
Proof’ targets
The expectation is that individual offices targeting
net zero carbon should seek to meet and exceed the
performance levels set out by the trajectory before
the procurement of renewable energy or offsets. The
The UK Green Building Council (UKGBC) has also
principles from UKGBC’s Net Zero Carbon Buildings
undertaken ‘top-down’ calculations to determine
Framework should then be followed to demonstrate
energy performance targets for offices based on
how net zero for operational energy has been
the available supply of zero carbon energy in 2050.
achieved. Where the energy performance targets are
Through consultation and direct engagement with
not achieved, this should be publicly disclosed with an
stakeholders, UKGBC identified a need for 60%
action plan setting out how the target will be met in
reduction in energy use from the office sector which
subsequent years.
translates to the ‘Paris Proof’ targets outlined in Figure
A1.2.
The trajectory does not differentiate between new
and existing offices, but it is expected that new offices
Net zero trajectory for offices
should aim to achieve the Paris Proof targets as soon
For offices looking to achieve net zero carbon for
as possible. Additionally, further consideration may
operational energy, the Paris Proof targets offer
be required for upgrading existing offices, including
an outcome-based approach to setting energy
understanding the embodied carbon impacts from
performance targets, Figure A1.3 sets out a trajectory
retrofit and any concessions for heritage buildings.
for tightening performance targets over the next
fifteen years for offices targeting net zero. The
These targets are intended to signpost to stakeholders
trajectory is based upon meeting current best practice
from across the offices sector the magnitude of energy
performance over the next five years, with ambitious
reductions required to achieve net zero by 2050. They
steps down towards the Paris Proof targets by 2035.
UKGBC energy performance targets for existing offices
Paris proof
target
Interim targets
Scope
Whole building energy
Base building energy
Tenant energy
Metric
2020-2025
2025-2030
2030-2035
2
2035-2050
kWhe/m (NIA)/yr
160
115
90
70
kWhe/m2 (GIA)/yr
130
90
70
55
DEC rating
D90
C65
B50
B40
kWhe/m2 (NLA)/yr
90
70
55
35
kWhe/m (GIA)/yr
70
55
45
30
NABERS star rating
4.5
5
5.5
6
kWhe/m2 (NLA)/yr
70
45
35
35
2
Figure A1.2 - UKGBC Energy performance targets for existing offices targeting net zero carbon for operational energy 9
Climate Emergency Design Guide
Figure A1.1 - Top down modelling results
Appendix 1
121
will challenge the construction and property sector to
re-imagine the way offices are designed, constructed
and operated, including moving towards in-use
performance as the verifiable metric for energy.
For
more
information
on
UKGBC’s
Paris
Dutch Green Building Council ‘Paris Proof’ targets
The Dutch Green Buildings Council has also developed
Proof
targets, please visit: https://www.ukgbc.org/news/
consultation-on-energy-performance-targets-foroffices-launched-to-target-net-zero/
the ‘Paris-proof’ methodology10 for quantifying the
order of magnitude of renewable energy that is likely to
be available for each building type in the Netherlands.
Their methodology allocates the expected practical
availability of renewable electricity between national
sectors (transport, industry, buildings etc..). For the
building sector, it subdivides the annually available
Base Building
100
→→ 50 kWh/m2..yr
B50
5*
→→ Shop with cooling, such as a supermarket: 150
kWh/m2..yr
6*
50
45
→→ Shop without cooling: 80 kWh/m2..yr
01
/0
1/
20
35
40
01
/0
1/
20
01
/0
1/
20
25
01
/0
1/
20
30
*(LER - Landlords Energy Rating)
0
Retail:
5.5*
40
20
B40
01
/0
1/
20
4.5*
60
01
/0
1/
20
Offices:
C65
120
renewable energy between the various main building
types. The following is an extract of their conclusions:
DEC rating
140
80
Whole Building
D90
01
/0
1/
20
160
20
Energy Intensity (kWhe/m2 NLA)
180
Figure A1.3 - UKGBC -Trajectory for offices targeting net zero
carbon (also indicating equivalent NABERS star rating)
Education:
→→ Primary education: 60 kWh/m2..yr
→→ Secondary education: 60 kWh/m2..yr
→→ Colleges and universities: 70 kWh/m2..yr
Healthcare:
→→ Hospital: 100 kWh/m2
→→ Daycare with accommodation: 80 kWh/m2..yr
→→ Daycare without overnight stay: 90 kWh/m2..yr
→→ Medical group practice: 80 kWh/m2..yr
Logistics / industrial:
→→ Industrial building with cooling: 80 kWh/m2..yr
→→ Industrial building without cooling: 50 kWh/m2..yr
LETI
Appendix 1
122
A1.2: The
Performance Gap
Summary
Background
A prerequisite to implementing the transition to
The performance gap can typically be described as
operational net zero targets advocated by LETI is
the deficit between energy predictions from building
bridging the gap between design and actual energy
compliance tools and actual measured energy in-use.
performance. Legislating for better standards has
This determines whether a building and its systems
no effect if the buildings that are produced do not
work as expected when occupied and the extent of
perform in practice.
the gap where not. Expectations may be defined by
regulatory targets, client and other requirements. The
In order to create the boundary conditions for a
performance gap does not solely relate to energy, it
shift in culture to happen, LETI propose to institute
has an impact on a number of variables including fire
an Assured Performance Framework (APF) and
safety, acoustic performance, comfort, lighting and
dutyholder
design quality. As such, a holistic approach is needed.
regime.
The
APF
revolves
around
independent reviews of design, construction and
operation linked to RIBA Plan of Work stages, feeding
The
learnings back into the loop using BSRIA Soft Landings
modelling for compliance (as opposed to modelling
principles. Central elements to this will be clear
for performance) does not allow the size of the
accountability through an accredited Performance
performance gap in the UK built environment to
Coordinator responsible for managing performance
be pinpointed. The national standard assessment
from inception through to completion and beyond;
methodology for compliance was conceived for
an overarching system for oversight of competence;
comparison purposes and relies upon a standardised
a Complaints Resolution Service giving consumers
set of operational assumptions. One of its key
a stronger voice; and more effective enforcement
deficiencies is in disregarding unregulated loads,
to deter non-compliance. LETI’s proposals align with
whose proportion of total energy use varies between
the proposed reform of the building safety regulatory
sectors, accounting for more than 25% in non-domestic
system and proposed legislation to provide better
buildings11.
redress for purchasers of new build homes. As such, it
gap in new buildings from a number of field testing
is hoped that there will be a legislative lever to uptake
programmes is consistently revealing underperforming
the proposal within the next iteration of the Building
envelopes (design vs as-built airtightness and thermal
Regulations.
transmittance) leading to higher heating demand
12,13,14
current
regulatory
Statistical
approach
evidence
of
based
on
performance
. Using conservative assumptions to normalise
the difference in heat balance scope, the Passivhaus
Trust15 has worked out that an average performance
gap expressed as the overall additional energy use
of a new build house amounts to 40% compared to
its EPC modelling and anecdotal evidence suggests
that it can be up to 500%. In order to deliver on LETI’s
Climate Emergency Design Guide
Appendix 1
123
net zero performance-based targets, it is therefore
crucial for this gap to be closed. Good design alone
is not sufficient, we need to measure and understand
the performance gap in order to identify ways of
closing it. This will be fundamental alongside the
integration of efficient fabric, systems, technologies
and performance monitoring to achieve net zero
buildings in operation.
Causes of performance gap
It is possible to identify key variables that, have a
knock-on effect on performance, as shown in Figure
A1.4.
A closer look into underperforming envelopes,
services and wider environmental indoor quality
contained in a growing body of literature unveils their
This briefing paper breaks down the causes leading
to a building failing to achieve its design intentions
and suggests methods for closing the performance
relationships with sub-optimal practices throughout
the entire process, and is detailed in the Table on the
following page.
gap based on three pillars – setting realistic targets,
ongoing performance monitoring and reduction
strategies applied to the full building life cycle.
Included in our recommendations is the institution of
an independent assured performance framework
and dutyholder regime.
Modelling tools
Design assumptions
Input errors
Bench
efficiencies
Buildability
PERFORMANCE
AS DESIGNED
Design
tolerances
Components
Material data
Build quality
Weather
Handover
PERFORMANCE
IN USE
Commissioning
Build
tolerances
In-situ
U-Values
Specification
Manuals
Durability
Documentation
Design
conflicts
Occupant
effects
Ad-hoc
design
PERFORMANCE
AT COMPLETION
Thermal
bypasses
System
efficiencies
Product
substitution
Usability
Metering
Controls
Maintenance
LETI
Figure A1.4 - Factors feeding into design, as-build
and in-use performance (Source: National Energy
Foundation, 2015).
Appendix 1
124
Common causes of underperformance
Causes of underperformance
Diagnostic tools
→→ Flawed design calculations (assumptions, inputs inaccuracies).
→→ Workmanship
→→ Poor handling and storage of materials on site, no understanding of their
energy impact
→→ Low quality of materials compared to design specifications
→→ Value engineering in favour of lower performance cost-engineered
alternatives
→→ Poor insulation detailing in particular at the interface, both design (use of
default thermal bridging coefficients) and construction phase
→→ No airtightness strategy
→→ Services penetrations interrupting the continuity of the airtightness layer.
→→ Fabric in-situ testing – standalone (heat flow meter) or whole
envelope (co-heating test)
→→ In-situ airtightness tests – standalone (pressurisation equipment,
smoke test) or whole envelope (hot
wire anemometer, tracer gas
→→ Inspection of construction quality
(infrared thermography + expert
diagnostic investigation)
→→ Installation quality checks
(photographs during construction).
Building fabric
Building services
→→ Lack of commissioning of services and suboptimal controls zoning / system
communication
→→ Over-sized systems
→→ Controls unfit for intended users of the building
→→ Poor coordination between designers and contractors
→→ Poor standard of installation / commissioning / handover / maintenance.
→→ Installation and commissioning
checks — evaluation of operation
and settings of the system
→→ Measurement and verification. In
particular mechanical ventilation
(power measurement + volumetric
airflow measurement
→→ Utilities metering, ideally
sub-metered energy use.
Indoor environmental quality
→→ Overheating due to suboptimal environmental design (orientation, thermal
inertia, glazing ratio, solar shading etc..), fabric and systems design (glazing
specifications e.g., total solar energy transmittance, ineffective ventilation
strategy, space heating controls difficult to operate or faulty, uninsulated
pipework contributing to unwanted heat gains…)
→→ Poor indoor air quality due to ineffective ventilation mechanisms, including
poor maintenance of mechanical ventilation
→→ Design is not user-centric (health and wellbeing not central in design).
→→ Services’ visual inspection and
performance testing
→→ Moisture monitoring (protimeter)
→→ Temperature, relative humidity and
CO2 / VOCs / NOx monitoring
→→ Occupant surveys using
standardised questionnaire e.g.
Building Use Studies (BUS) surveys
→→ Qualitative semi-structured
interviews with the occupants.
Figure A1.5 - Review of common causes of under performance across building envelopes, services and indoor environmental quality.
Climate Emergency Design Guide
Appendix 1
125
Closing the performance gap
Throughout operation, ongoing monitoring would
In simple terms, closing the performance gap relies
use. For the first year of operation a ‘bottom-up’
on three key pillars: (i) set realistic targets, (ii) monitor
ongoing performance, and (iii) put in place a process
to reduce energy use against target.
identify areas to focus on in order to drive down energy
approach may be useful, with each energy end
use compared to its predicted performance — this
process would help refine the targets as much as it will
For existing buildings, target-setting can take the
form of applying benchmark data or commissioning
a detailed simulation model. For new buildings,
closing the performance gap starts at the concept
design phase. Preliminary performance and energy
use targets should be set, and detailed predicted
energy use modelling undertaken to support the
design process. Target-setting should encompass the
full spectrum of intended operational parameters
and should be undertaken with input from project
stakeholders including building users.
identify opportunities to reduce consumption.
It is critical to ensure that performance is monitored
through the life of the building — changes to
maintenance strategies, occupant pattern and other
factors mean that ‘set and forget’ is almost certain to
result in performance problems over time. Generally
a ‘top-down’ approach is recommended: high level
reporting against overall targets with a ‘deep dive’ to
end-use level where problems are identified.
Against this backdrop, a more effective accountability
For new buildings, careful monitoring of the project
delivery during construction and handover must take
place, followed by verification and commissioning
to ensure that the design is realised in the delivery of
the building. Performance targets should be refined
and linked to the monitoring system to enable simple
framework from design through construction and
occupation of the buildings is crucial to create a real
shift in culture across the industry. Clearly identified
individuals directly accountable for performance
should be mandated. This is similar to the reform for the
building safety regulatory system proposed after the
ongoing comparison.
123
Set realistic targets
Figure A1.6
LETI
Monitor
Identify reduction
performance
strategies
- How to close the performance gap
Appendix 1
126
Hackitt’s review, and is in line with the Government’s
→→ RIBA 3-4: Detailed review of design from a
wider commitment to improve redress in the housing
performance angle, feeding findings back into
market. Such a dutyholder regime would provide
the loop before construction works commence.
clear accountability for managing performance so
Appropriate energy modelling (i.e. modelling for
that consumers’ interests in getting the expected
reality as opposed to compliance) to ensure that
build quality are protected, whilst holding developers
energy performance is not significantly affected
to account.
among the many trade-offs that must be made
through the design process.
The new regime ought to give consumers a stronger
→→ RIBA 5-6: on-site supervision carried out by a
voice and set out clear routes of escalation if things
named individual. Robust testing and verification
go wrong. A bespoke Complaints Resolution Service
regime.
could be established as a single point of access
where consumers know they could turn for help.
→→ Operation: continuous monitoring of energy
performance. Ongoing reward and recognition
for
meeting
performance
targets
creates
Finally, enforcement action shall be strengthened to
incentive to further reduce consumption and
deter non-compliance with the new regime. Effective
improve user satisfaction. Strategies to include
powers of intervention and sanctions shall be given to
approaches for putting building users at the
the overseeing regulator.
heart of the performance question through post
occupancy evaluation.
Conclusion
The legislative mechanisms required to be put in place
The causes of the performance gap are vast and
varied, and span across many stakeholders.
achieving net zero carbon, making addressing it a
priority to a successful transition to outcome-focused
targets in the built environment. In order to move
away from the status quo, LETI advocates focusing on
performance.
of performance from inception to completion (in a
similar fashion to the PAS 2035 Retrofit Coordinator)
is created. This, alongside the existing Government’s
initiatives
to
strengthen
quality
and
standards
putting the consumer at the centre of the journey,
would create a market and the conditions for better
performance.
We support the institution of an independent assured
performance process. This could take the shape of
independent design and construction review and
support input linked to RIBA stages.
0-2:
is advocated that the role of qualified and accredited
Performance Coordinator, responsible for all aspects
Closing the performance gap is instrumental in
→→ RIBA
are outside the scope of this document. Nonetheless it
Review
of
realistic
targets
that
encompass all energy uses in the building and
the underpinning
environmental design vision
and strategy.
Climate Emergency Design Guide
Critical to all of this will be feeding lessons back into
the loop using Soft Landings and standardisation of
procedures.
Appendix 1
127
References
10 - DGBC, Paris Proof Targets. [Online]. Available
from: https://www.dgbc.nl/themas/paris-proof
1 - National Grid ‘Future Energy Scenarios’ (2018)
11 - Cohen R ‘The Performance Gap in Non-Domestic
2 - Department for Business, Energy & Industrial
Buildings’ Presented at Ecobuild 2013. London/
Strategy ‘Energy Consumption in the UK, End Use
Swindon: Verco/Technology Strategy Board (2013)
Tables’ (2018)
12 - ‘Building Performance Evaluation Programme:
3 - Valuation Office Agency ‘Non-domestic rating:
findings from domestic projects. Making reality
Business Floorspace tables’ (2019)
match design’ Innovate UK (2016)
4 - Colin Jones and Edward Trevillion, Heriot Watt
13 - ‘Building Performance Evaluation Programme:
University ‘Commercial Real Estate and Scottish
findings from non-domestic projects. Getting the best
Economy’ commissioned by the Scottish Property
from buildings’ Innovate UK (2016)
Foundation (2015)
14 - ’Building Performance Evaluation Meta-Analysis.
5 - Office for National Statistics ‘Families and
Insights from social housing projects’ National Energy
Households’ (2019)
Foundation (2015)
6 - Department for Communities, Northern Ireland
15 - Passivhaus: the route to zero carbon? London:
Statistics & Research Agency ‘Northern Ireland
Passivhaus Trust (2019)
Housing Statistics 2017-2018’ ISBN 978-1-90410598-5 (2018, revised 2019)measuring-reporting/
design-performance
7 - Ministry of Housing, Communities & Local
Government, ‘English Housing Survey, Headline
Report, 2017-18’ ISBN: 978-1-4098-5406-7 (2019)
8 - Valuation Office Agency, ‘NDR Business
Floorspace Tables 2019’ (2019)
9 - UKGBC, Net zero carbon: energy performance
targets for offices [Online]. Available from: https://
www.ukgbc.org/wp-content/uploads/2020/01/
UKGBC-Net-Zero-Carbon-Energy-PerformanceTargets-for-Offices.pdf
LETI
Appendix 2
128
A2.1: Embodied
carbon reduction
calculations
Inventory x Impacts =
Estimate of
Estimate of
Estimate
quantities of
environmental
of total
materials and
impacts for
environmental
processes in
each material
impact of
building
and process
building
Summary
This Appendix provides a description of the process for
carrying out embodied carbon calculations. It also
E.g.
goes into details on the tools available and how to
100 kg steel
x
0.43 kgCO2e
=
43 kg CO2e
50 kg glass
x
1.064 kgCO2e
=
53.2 kg CO2e
consider operational energy within whole life carbon
calculations. There is a section on the Scope of Work
for life cycle assessment that provides supporting
information for how to approach and engage a
Total
consultant.
Figure A2.1 - Simple example of LCA calculation process (Source:
Carbon leadership forum practice guide 2019 p11)
Conducting life cycle assessment
(LCA)
1.
Embodied carbon refers to the amount of greenhouse
gas emissions created during the processes of material
extraction, manufacturing, transport, construction,
maintenance, repair, refurbishment, replacement,
demolition and disposal. Whole life carbon refers to
embodied carbon plus emissions related to energy
and water use. The purpose of assessing WLC is to
move towards a building or a product that generates
lower carbon emissions over its whole life.
This can be measured through a life cycle assessment
which accounts for emissions at every stage of the
entire life cycle of a building’s materials and products.
Typically, a LCA of proposed building consists of 4
steps:
1.
Define goal and boundaries.
2.
Estimate quantities of materials, products and
processes in the building.
3.
Assess the carbon equivalent emissions for each
Define goal and scope
The first step is to define the goal, meaning the
reasons for carrying out the LCA study. To ensure
consistency, it is necessary to define the boundaries
for the calculation.
The site scope – a clear indication of the project site
and which buildings are included within the study.
The building element scope – a clear indication of
the building’s parts included within the study. It is
important to have a consistent approach in carrying
out a building LCA with regard to which building parts
should be considered and assessed. The BREEAM
New Construction 2018 UK – Mat 01 guide provides
a reference for the industry, defining lists of In-Scope
and Out of Scope building elements based upon the
RICS New Rules of Measurement (NRM) classification
system (N.B. this is not applicable for fit-out, Cat A, Cat
B assessments).
material/product and process and then sum
them to obtain the overall carbon footprint (See
Figure A2.1).
4.
Interpret the results, refine and re-iterate if
needed.
Climate Emergency Design Guide
SIGNPOST Embodied Carbon Primer - Appendix
11 - In scope and out of scope
Appendix 2
129
Measurement unit - which unit should the results be
SIGNPOST Embodied Carbon Primer - Appendix
presented in. For embodied carbon, it is usually kg of
3 - How to measure embodied carbon
CO2 equivalent (CO2e) over 100 years.
The (reference) Study Period - period of time
Figure A2.2 shows the activities within each stage
(A-C) and supplementary Module D as laid out in EN
considered for the LCA study, this will affect the results
15978:
related to the in-use stage, due to replacement of
→→ Cradle to Gate: Stage A1-A3.
building parts and systems. The study period should
→→ Cradle to Practical Completion of Works: Stages
be defined in order to establish the building’s whole
A1-A3 & A4-A5.
expected life and the related service life of building
→→ Use: B1-7
parts and systems. 60 years is often taken as the study
→→ End of Life: C1-4
period.
→→ Cradle to Grave: Stages A-B-C
The system boundary / Life cycle stages - which life
→→ Cradle to Cradle: Stages A-B-C & Module D
cycle stages (as defined by EN 15978) are considered
There
in the LCA study. The life cycle stages assessed
methodology of specific subjects which need to be
must be comparable for each iteration of the
clearly defined such as Biogenic carbon (often also
assessment.
called Timber sequestration).
are
some
controversies
concerning
Whole life carbon
Circular economy
Embodied carbon
stage
stage
life cycle
B5
C1
Operational carbon
B6
Operational energy
B7
Operational water
Cradle to gate
Cradle to practical completion
Cradle to grave
Cradle to cradle
Figure A2.2 - System Boundary: EN 15978:2011 Display of modular information for the
different stages of the building assessment
LETI
C2
C3
C4
D
Benefits & Loads
Disposal
B4
Deconstruction &
demolition
B3
Replacement
B2
Refurbishment
B1
Repair
A5
Maintenance
A4
Waste processing
Beyond building
stage
Transport
End of life
Use
A3
Manufacturing
A2
Transport
Raw material
supply
A1
In-use
Construction &
installation process
stage
Construction
Transport
Product
Reuse
Recovery
Recycling
the
Appendix 2
130
2.
Estimate quantities of materials, products and
3.
Assess the environmental impact
processes in the building
Embodied Carbon
Embodied Carbon
At building level, this requires multiplying the quantities
In the case of the embodied carbon component
of the material product with its environmental
of a LCA of a building, the estimate of quantities of
impacts for each life cycle stage of the building. It
materials takes place at two different scales.
is recommended to use specific tools which gather
all the information in the same place with an inbuilt
At the building level: Listing the quantities can be done
database. BIM based LCA tools have the advantage,
manually by listing all materials, products and systems
compared to other tools, to be linked to the BIM model
within the building, however it is be recommended to
which detects automatically the different material
use BIM models to identify the different quantities.
quantities of building parts within the building.
At the product level: Once all products are identified
within the building, the inner parts and processes
SIGNPOST Embodied Carbon Primer - Appendix
involved in making the product, in use and end of
3 - How to measure embodied carbon
life of the products needs to be listed as well. This is a
very tedious and time-consuming process; therefore,
Different life cycle impact assessment methods
design teams should refer to Environmental Product
currently exist, so the method used by the tool at
Declarations from manufactures or other generic
building level should be consistent with the methods
information from the Industry which already have
used at the product level (from EPDs for instance).
calculated the environmental impacts of the product
throughout the life cycle stages.
Operational Carbon
It is important to realistically estimate operational
Operational Carbon
carbon emissions. It is recommended to use annual
It is important to realistically estimate the operational
lifetime carbon emissions factors, at present this is 0.07
energy of the building. For design stage calculations
kgCO2/kWh for the average content of the UK grid
use predictive modelling allowing for a performance
over the next 30 years.
gap to estimate energy consumption. If this is not
available use benchmark figures relevant to the
4.
building type and location. Do not use SAP/SBEM
Conducting life cycle assessments is an iterative
Interpret the results, refine and re-iterate
(calculations carried out for Building Regulations) for
process by nature. As the design teams are exploring
calculating operational energy as these calculations
different design options, it is a tool to inform on the
are for compliance only and do not predict energy
environmental impacts to help make decisions on
consumption.
what is the best solution from an environmental point
of view.
SIGNPOST Embodied Carbon Primer - Appendix
3 - How to measure embodied carbon
Climate Emergency Design Guide
Appendix 2
131
The below step sequence lists how to model embodied
Cycle Impact Assessment (LCIA) methodologies, data
carbon reductions:
source, standards they follow, and standards they
1.
Create a ‘baseline model’
comply with. Appendix 4 of the Embodied Carbon
2.
Follow the ‘rules of thumb’ in the Embodied
Primer gives a few examples to demonstrate the
Carbon Primer.
range and explains the advantage of BIM (plug-in)
Understand the big-ticket items – the building
based tools.
3.
elements that have the most impact
4.
Develop the carbon reduction strategy
This appendix also provides some valuable pointers
5.
Determine an ‘optimised model’ and ‘% carbon
on what to consider when using LCA tools such as
reduction’
geographical location of the database, data used
SIGNPOST Embodied Carbon Primer - Appendix
at different project stages and the importance of
6 - Rules of thumb
breaking the project (and BIM model) down into more
accurately measurable components.
The baseline model
The baseline must be defined using the first design
iteration before any carbon saving measures are
introduced. It is imperative to build a consistent
and solid baseline model in order to calculate the
reductions brought about by any carbon reduction
measures. The baseline will highlight which building
elements generate the most carbon emissions,
allowing the designer to focus attention on areas
where greater carbon mitigation interventions are
possible.
SIGNPOST Embodied Carbon Primer - Appendix
4 - LCA tools
Scope of work for life cycle
assessment
To meaningfully inform a carbon reduction strategy,
whole life carbon calculations should be carried
out through a life cycle assessment (LCA). This can
be carried out by an in-house specialist or by a
dedicated LCA consultant.
SIGNPOST Embodied Carbon Primer - Appendix
12 - Baseline specifications
Firstly, it is essential that a client brief is developed
to outline the client’s ambitions and objectives. For
Embodied Carbon reduction strategy
Subsequently,
an
embodied
carbon
reduction
strategy would identify a list of alternative measures
and quantify the magnitude of carbon abatement
that each would provide.
Life cycle assessment tools
A number of tools to conduct life cycle assessment
for buildings exist today. They can differ by their Life
LETI
example, the brief may include a target expressed
in kg CO2e/m2, a percentage reduction in embodied
carbon, or outline a goal such as ‘to create the
client’s lowest embodied carbon office building’. For
detailed guidance read UKGBC’s ‘Embodied Carbon:
Developing a Client Brief’.
SIGNPOST Embodied Carbon Primer - Appendix
2 - Scope of work for LCA
Appendix 2
132
A2.2: Materials
Guide
Summary
embodied carbon. OPC, the binder in concrete, is
When it comes to materials choices there is no
minerals) and gypsum.
single solution to designing low-embodied carbon
buildings. A key consideration is to ensure that each
material should be chosen only where it is the best at
performing the function it is required to perform with
the lowest whole life carbon impact. It may be that
higher embodied carbon materials are chosen due
to their roles in reducing operational carbon over a
building’s lifetime.
Wherever possible, local reclaimed materials should
be used as this also reduces delivery distances and
packaging. An Environmental Product Declaration
(EPD), obtained via a thorough Life Cycle Analysis
(LCA) of a material or component can be used to
assess the environmental impacts of a specification
choice. The recyclability of the material at the end of
the building’s useful life should also be considered.
For any material that is being specified in a building,
always ask suppliers:
→→ Do you have an EPD?
→→ How can your product be recycled/reused?
→→ What is the embodied carbon of your product,
and what are you doing to reduce this?
Concrete
Concrete is utilised for infrastructure, foundations,
floors, walls, structural frames. As a mixture of cement
(usually Ordinary Portland cement (OPC)) and
aggregate, concrete can be produced to different
compressive and tensile strengths and with variations
in aggregates and binders. Higher compressive
strength will usually come at a cost of higher
Climate Emergency Design Guide
produced from clinker (from heated limestone and
Key considerations:
→→ Slimming off excess where structurally viable to
save in material usage;
→→ Reducing and substituting OPC with recycled
or sustainably-sourced content, whilst ensuring
strength and integrity is retained (examples:
GGBS and PFA);
→→ Considering a structural grid and superstructure
design to enable different use types and
deconstruction for use elsewhere when the
building has got to the end of its life;
→→ Considering reusable plastic formwork;
→→ Standardising detailing to enable repetition of
reinforcement and also to enable formwork to be
re-used multiple times.
Timber/wood
Wood should be sourced from sustainably managed
forests. Carbon sequestration rates in trees are
dependent on many variables – maturity, forest type,
local climate, soil and forest management - the rate
reduces as a tree reaches maturity.
Key considerations:
→→ Sustainable sourcing is vital and deforestation is a
serious issue. Only specify timber from sustainably
managed sources;
→→ Most engineered timbers are currently shipped
in to the UK, consideration should therefore be
given to the carbon emissions of transportation
when compared with locally available materials;
→→ Engineered timbers that use glues/adhesives in
Appendix 2
133
the lamination process may be more difficult to
reuse;
embodied carbon but strong enough for the
→→ Products such as OSB (oriented strand board)
are made using glues and resins which can emit
VOCs, affecting indoor air quality;
→→ Treatment of timber may affect end of life
reusability;
→→ Also
or
→→ Consider using a mortar mix that is low in
consider
interlocking
reversible
mechanical
strategies
which
fixings
require
no
additional materials.
purpose while allowing the brick to be easily
reclaimed.
Structural steel
51% of global steel is used for construction. Steel is
used in a wide range of construction projects ranging
from single dwellings to large scale infrastructure.
Key considerations:
Brick
→→ To
Brick is a popular choice for walls. Brick is produced
by cutting a ‘slug’ of clay into units which are fired at
help
with
re-use,
use
standard
bolted
connection details and clamped fittings in
preference to welded joints;
around 2,000 degrees. Emissions come from both the
→→ Where feasible, ensure that steel is free from
fossil fuels used in the heating and from the processes
coatings or coverings that will prevent visual
related to all clay products (e.g. extraction). On larger
assessment of potential for re-use; and,
scale buildings brick slips, mounted on steel fixings and
→→ Identify
the
origin
and
properties
of
the
used as a rainscreen, are often used to save time and
component
costs. However, brick slips have a higher embodied
stamping, and keep an inventory of products
carbon on a per kilo basis due to the brackets and
(material passport) so that products can be
fixings.
re-used once the building has reached.
bar-coding,
e-tagging
or
Aluminium
Key considerations:
→→ Local
by
sourced
The production of primary aluminium requires very
wherever possible. An unfired brick system with
high electricity consumption almost 10 times that of
much lower embodied carbon may be suitable
steel. Owing to the very energy intensive processing
for internal non-load bearing walls and can also
involved, embodied carbon is very high, especially
help with humidity regulation;
when used in larger volumes. Aluminium is highly
reclaimed
brick
should
be
→→ For a circular approach, it is advised to use
recyclable, with properties that do not diminish as
a mortar which is softer than the brick. Hard
the material is re-used. Worldwide, around 75% of all
concrete mortars will not remove easily from
aluminium produced is still in use. Recycling uses only
brickwork, resulting in damaged and broken
around 5% of the energy needed to produce primary
bricks;
aluminium. Inventories of all aluminium components
→→ Damaged bricks can be ground up and used in
aggregates;
LETI
should be kept to ensure all material is tracked and
can be recycled in the future.
Appendix 2
134
Key considerations:
→→ Long transportation routes in between extraction,
processing and fabrication adds to embodied
energy. As well as energy intensity, bauxite
processing is very water intensive;
→→ The residue from aluminium processing is in the
order of 120 million tonnes per year and is toxic to
animal and plant life. Most of this residue is stored
in holding ponds as there are virtually no further
suitable applications for re-use.
Glass
Soda-lime glass accounts for 90% of manufactured
glass. It is made up of 70-74% silica, along with sodium
carbonate, lime, magnesium oxide and aluminium
oxide in order to enhance its properties. With its
unique translucent properties, glass has a variety
of uses. Recycled glass can have a second use as
insulation or aggregate.
Key considerations:
→→ Glass requires the use of non-renewable natural
raw materials - sand and minerals;
→→ Consider the whole life carbon of any project low embodied carbon is a false economy if heat
is easily lost in the operational phase; and,
→→ Where framing is required, timber is usually the
best option. It has a longer useful life than PVC
and superior thermal performance than metals.
SIGNPOST Embodied Carbon Primer - Appendix
8 - Material guides
Climate Emergency Design Guide
Appendix 2
135
LETI
Appendix 3
136
A3.1: Hydrogen
Hydrogen conversion of natural
gas networks
The following publications by and for the Committee
on Climate Change (CCC) assess the potential
for hydrogen as part of a net zero carbon United
Kingdom. In essence, the indications are that
hydrogen has a key role to play, but should be focused
on selective sectors and perhaps regions. When 80%
carbon emissions reductions were considered as
target, hydrogen conversion of natural gas networks
was seen to be cost comparable with other scenarios.
However, conversion of the national gas network as
part of achieving net zero carbon is seen to be a
equivalent of twice the current global production of
hydrogen (UK having approximately 1% of the global
population).
There has been considerable interest in hybrid
heat pumps that use hydrogen to cope with peak
demands. However, a current research project shortly
to be published by the IEA (International Energy
Agency) Heat Pump Technologies TCP Annex 45 has
identified that the product development has been
largely curtailed because nations like Germany
(where many of the potential manufacturers are
based) have indicated, like the CCC, that renewable
hydrogen may only be available for selective sectors.
significantly more expensive option.
In addition, switching the gas grid to hydrogen would
The large-scale conversion of natural gas to hydrogen
only for peak lopping capacity, and hence increase
does produce CO2. Therefore, for this technology
to be considered net zero carbon, it would need to
be subject to Carbon Capture and Storage (CCS).
Replacing the gas supply network would also involve
very large-scale annual storage of hydrogen to meet
the winter peak heating demand profile, particularly
as its conversion may need to use summertime ‘spare’
renewable grid electricity. These issues significantly
impact on the overall costs of this option. However,
there is lower-cost potential for regional gas grid
conversion local to where natural gas comes ashore,
where there are geological opportunities for CCS, in
association with large scale storage. There are also
other niche sectors, like long haul aviation, that may
end up being the priority for use of renewably sourced
hydrogen.
As an indicator of scale, a switch of the complete
UK gas network to carry hydrogen would require the
Climate Emergency Design Guide
have a lower return on investment should it be used
the relative cost of hydrogen as a building energy
supply solution.
Consequently, this report takes the view that net zero
carbon hydrogen is unlikely to be an option for heating
the vast majority of new and existing buildings.
Further Reading:
→→ “Hydrogen in a low carbon economy” Committee
on Climate Change. [Online]. Available from:
h t t p s : // w w w. t h e c c c . o r g . u k / w p - c o n t e n t/
uploads/2018/11/Hydrogen-in-a-low-carboneconomy.pdf
→→ “Analysis of alternative UK heat decarbonisation
pathways” Imperial College for the Committee
on Climate Change. [Online]. Available from:
h t t p s : // w w w. t h e c c c . o r g . u k / p u b l i c a t i o n /
analysis-of-alternative-uk-heat-decarbonisationpathways/
Appendix 3
137
A3.2: CO2 refrigerant
heat pumps
There is increasing interest and development going
heat uplifts. This difference would normally require
into heat pumps using CO2 as a refrigerant (ASHRAE
a significant reconfiguring of the building heat
refrigerant designation number R-744). Besides having
zero Ozone Depletion Potential (ODP), CO2 also has an
ultra-low Global Warming Potential (GWP) of 1 (unlike
most currently used refrigerants, the most common
distribution system.
While not specifically referred to in this report, CO2
heat pumps offer future technology potential, albeit
of which typically have GWPs in the range of 1400
initial performance claims may need to be qualified
to 2100), is non-flammable (unlike almost all other
given the past performance gap between design
natural refrigerants) and is non-toxic (unlike ammonia,
expectations and operational performance for most
which is often used as a refrigerant in large scale
current heat-pump systems.
industrial applications). But perhaps of most interest in
the context of Future Heat for buildings is the ability of
Further Reading:
CO2 heat pumps to deliver domestic hot water (DHW)
→→ “Recent Advances in Transcritical CO2 (R744)
with most currently available heat pumps. Japan has
Huojun Yang, Sumathy Krishnan and Jongchul
been leading the research and product development
Song.
of heat pumps suitable for buildings of a range of
mdpi.com/1996-1073/12/3/457/pdf
temperatures at relatively high efficiencies compared
scales down to individual dwellings.
Existing heat pumps cannot be switched to CO2 as
a refrigerant:
firstly, the system must be designed
specifically for it, not least because it operates
at significantly higher pressures than traditional
heat pumps. Technically, this is fully solvable and,
indeed, smaller bore pipework needed for smaller
applications is inherently more pressure compatible.
It is expected that all CO2 refrigerant systems would
be factory sealed so avoiding any site refrigerant
pipework assembly.
Secondly,
CO2
heat
pumps
generally
require
large temperature differences in the fluid used to
remove heat from the heat pump, whereas most
other refrigerants can only deliver very modest fluid
LETI
Heat Pump System: A Review” Rajib Uddin Rony,
[Online]. Available from: https://www.
Appendix 3
138
A3.3: Reducing
heat demand at
point of use
Figure A.3.1 opposite shows indicative building design
parameters expected to achieve the performance
levels proposed for space heating and for domestic
hot water (DHW). The same values are anticipated for
most occupied building types, including offices and
residential developments.
Climate Emergency Design Guide
Appendix 3
139
Indicative building design parameters
Heating: installed capacity of heating plant of 10 W/m2 of floor area
Roof & ground U-value
0.09 - 0.12 W/m2.K
Wall U-value
0.10 - 0.15 W/m2.K
Window & door
U-value
1.0 W/m2.K
Overall including frame
Window to wall ratio
<35%
Correlated with overheating avoidance & daylight
Envelope airtightness
<0.6
Air changes per hour @ 50Pa test pressure
Ventilation heat
recovery
90%
For minimum fresh air during heating season only
Heat-pump control
24 hr enabled
Night setback to avoid morning boost grid demand
Domestic hot water: installed capacity of heating plant of 9 W/m2
Low-demand outlets
EWL ‘Green’ rated
European rating (e.g.: shower 6 L/min)
Maximum dead-legs
Max 1 litre volume
Has increased significance with low demand
Smoothing demand
DHW storage
Individual dwelling with extended recovery
Smoothing demand
Community wide
Using diversity to meet installed capacity target
Commercial DHW
Use heat-pump
COP of 250% instead of 100% for direct-electric
Figure A3.1 - indicative building design parameters expected to achieve the performance levels proposed for space heating and
for domestic hot water (DHW)
Notes:
→→ EWL water outlet rating system http://www.europeanwaterlabel.eu/
→→ Consider Heat Autonomy as an option for harnessing waste heat, reducing system costs, reducing standing losses and
reducing grid peaks.
→→ Consider 5th Generation heat-share ambient loop networks for harnessing waste heat (e.g.: heat rejection from cooling
plant).
LETI
Appendix 3
140
A3.4: Typical buildings
Indicative example measures for typical buildings
Heat measures for typical
Small scale
Medium scale
Large scale
building types
residential
residential
residential
Office
School
01. Enhanced envelope thermal
performance
P
P
P
P
P
02. Mechanical ventilation heat
recovery
P
P
P
P
P
03. 10 W/m2 peak heating capacity
P
P
P
P
P
04. ‘Green’ rated EWL hot water
outlets
P
P
P
P
P
05. DHW storage and trickle charge
P
P
P
P
P
06. Exhaust air heat-pump
P
P
P
O
O
07. In room water-source heat-pump
O
O
O
P
P
08. Room exposed thermal mass to
smooth peak demands
P
P
P
P
P
09. Building heat-share water
network
O
O
O
P
P
10. Water source heat-pump
connection to community heatshare network
O
P
P
P
P
11. All-electric for access to grid
renewables
P
P
P
P
P
12. Roof area PV suffice for on-site
net-zero-carbon
P
P
O
P
P
Figure A3.2 - indicative example measure that can be used in typical buildings
Notes:
→→ New EU water outlet rating system (EWL), e.g. certified ‘Green’
grade 6 litre per minute shower heads (without the use of flow
restrictors).
→→ EAHP using residual waste heat in extract ventilation after
MVHR for supply both space heating top-up and DHW.
→→ Room WSHPs providing heating (and cooling), both sourced
from building wide heat sharing ambient loop network.
→→ Room exposed thermal mass to smooth peak demands by
~25% for buildings with regular peak loads. Less data exists on
benefits in average dwellings where users/systems tend to be
more diverse.
→→ Building heat sharing ambient loop water network operating
→→
→→
at 15-25˚C allows redistribution and reuse of waste heat within
building.
Connection to community wide heat sharing ambient loop
network to allow any excess heat from cooling to be made
available to other buildings – in particular, for difficult to
upgrade residential with residual heating and DHW demand.
Fossil fuel free means that the heating system uses electricity,
not gas or oil. This means that all residual energy can access
grid renewables. The extent of this would need to be within
a fair share of renewables capacity input into the grid and
would need demand management to ensure demand
periods are matched to grid renewables supply availability.
Appendix 3
141
Small scale residential – terraced or semi-detached
Commercial offices
homes
→→ Enhanced envelope thermal insulation with
→→ Enhanced envelope thermal insulation and
MVHR.
→→ Maximum ~10W/m² peak heat loss (including
MVHR.
→→ Maximum ~10 W/m² peak heat loss (including
ventilation).
→→ ‘Green’ EWL hot water outlets (e.g. certified 6
litre per minute shower heads, not using flow
ventilation).
→→ ‘Green’ EWL hot water outlets (e.g. certified 6
litre per minute shower heads, not using flow
restrictors).
→→ Room WSHPs providing heating and cooling - both
restrictors).
→→ EAHP using residual waste heat in extract
sourced from heat sharing network operating at
ventilation for both space heating top-up and
15-25°C. This allows redistribution and reuse of
DHW.
waste heat within the building.
→→ DHW storage trickle charged by EAHP.
→→ All-electric i.
→→ All-electric building i, using room exposed thermal
mass to smooth peak demands by 25%.
→→ Connection to community wide heat sharing
Medium scale residential – up to 4 storeys
network to allow any excess heat from cooling
→→ Enhanced envelope thermal insulation and
to be made available to other buildings – in
MVHR.
particular,
→→ Maximum ~10W/m² peak heat loss (including
ventilation).
difficult-to-upgrade
residential
building stock with residual heating and DHW
demand.
→→ ‘Green’ EWL hot water outlets (e.g. certified 6
litre per minute shower heads, not using flow
Schools – primary or secondary
restrictors).
→→ Enhanced envelope thermal insulation with
→→ EAHP using residual waste heat in extract
ventilation for both space heating top-up and
DHW.
MVHR.
→→ Maximum ~10W/m² peak heat loss (including
ventilation).
→→ DHW storage trickle charged by EAHP
→→ All-electric i .
→→ ‘Green’ EWL hot water outlets (e.g. certified 6
litre per minute shower heads, not using flow
restrictors).
Large scale residential – more than 4 storeys
→→ Enhanced envelope thermal insulation and
MVHR.
→→ Room WSHPs providing heating and cooling - both
sourced from heat sharing network operating at
15-25°C. This allows redistribution and reuse of
→→ Maximum ~10W/m² peak heat loss (including
ventilation).
→→ ‘Green’ EWL hot water outlets (e.g. certified 6
litre per minute shower heads, not using flow
waste heat within the building.
→→ All-electric building i, using room exposed thermal
mass to smooth peak demands by 25%.
→→ Connection to community wide heat sharing
network to allow any excess heat from cooling
restrictors).
→→ EAHP using residual waste heat in extract
to be made available to other buildings – in
ventilation for both space heating top-up and
particular,
difficult-to-upgrade
residential
DHW.
building stock with residual heating and DHW
→→ DHW storage trickle charged by EAHP
demand.
→→ All-electric .
i - This means that the building does not burn fossil fuels on site.
i
Heating and hot water can be generated by heat pumps. (It
does not mean that direct electric is used for heating and hot
water).
Appendix 4
142
A4.1: Demand
response and
energy storage
Demand Response and energy flexibility can take
Almost all participants today will use some form
place on any energy distribution network where
of remote control and electrical metering, usually
a sizeable number of consumers and generators
referred to as an internet of things (IoT) device. These
share the same network. Flexibility programs have
systems collect electrical data and can control a
mostly evolved alongside the incentives and markets
specific part of a system.
that the National Grid and other bodies have
created. Programs for emergency backup provision
These IoT systems might directly control a device (such
or reduction such as STOR (Short Term Operating
as setting the output of a battery inverter) or perhaps
Reserve) and FFR (Firm Frequency Response) have set
link into an existing BMS system. Electrical data is
the standards. Various companies have developed
almost always collected to prove that an action has
technology and systems in order to efficiently
taken place and to monitor its progress. Naturally, this
participate.
requires that electrical data is only collected from the
flexible assets, so a good metering strategy is essential.
In general, the aim of all of these market systems is
There also tends to be a larger management system
not to reduce carbon, but to balance demand and
which collects the data, sends out the signals for
supply in the electrical network. In the future, energy
when actions must take place and monitors ongoing
markets will continue to evolve and have been
actions.
increasingly accepting smaller amounts of energy
flexibility for more specific applications.
Today, most participation in national energy flexibility
initiatives can be grouped under the following
categories:
→→ Direct participation of large industrial consumers
(e.g. steelworks, aluminium smelting)
→→ Standalone energy storage projects (e.g. >1MW
Battery Installations)
→→ Aggregation of a large number of medium size
flexible assets and storage (e.g. large chillers,
pumps, small batteries)
Climate Emergency Design Guide
Appendix 4
143
A4.2: Direct
carbon savings
using a battery
Most demand response incentives are structured
→→ Basic National Grid flexibility program, Dynamic
around system resiliency. However, let’s explore the
FFR (this is the most common control strategy for
possibility of a purely carbon reduction focused
a battery)
flexibility scheme.
→→ Buy low carbon, sell high carbon.
In carbon models today, fixed carbon intensity is
In general, participating in any form of energy
commonly used for all electrical consumption in a
flexibility program will be carbon positive (unless your
building. Hour to hour, minute to minute, different
flexible asset is some form of fossil fuel generation,
generation sources are contributing to the overall
then it would require further proof). At times when
supply on the electrical network. This means that the
energy flexibility is required, participating assets tend
carbon intensity of the grid is always changing. See
to be replacing the output of fossil fuels like coal and
the Figure A4.1. This dynamic carbon intensity allows
gas. Notably, if using storage, this also means that the
us to trade using it as a metric.
time you charge your storage will be as important as
when you discharge it.
For example, we’ll assume that we have a medium
battery (100kW) and for comparison, we will compare
three strategies:
→→ Buy low, sell high, market exposed strategy (this
Carbon Intensity (gCO2/kWh)
may not be the highest money earning strategy)
600
500
400
300
200
100
0
12- Aug 00:00
12- Aug 12:00
13- Aug 12:00
13- Aug 00:00
Time (Local Time)
Actual
Forecast
Figure A4.1 - Fluctuating carbon intensity (source https://carbonintensity.org.uk/)
LETI
14- Aug 00:00
14- Aug 12:00
Appendix 4
144
A4.3: Theoretical
stories of energy
flexibility
A4.4: Metering
requirements
Below are some examples of theoretical participants
Dedicated metering should be required for all flexible
in energy flexibility initiatives.
assets, this is an important part of proving that flexibility
has taken place, and metering of a good standard is
Energy Manager
already a requirement of paid programs.
“I am an energy manager in charge of several
schools. In order to reduce our energy bill, we started
The level of metering required is tiered in that more
to participate in National Grid flexibility programs,
complicated programs or larger pots have more
agreeing to turn down our chillers at periods of grid
stringent metering requirements, but generally have
stress. Now that the control and metering is in place,
higher financial rewards. This should be considered
we have been able to better understand our energy
when developing the metering strategy.
use and have made further efficiency improvements.
As part of a student led project, we will be using the
LETI would advise that you plan for the long term
improved control to turn off our chillers when coal
because
plants are generating on the network, in order to
stringent over time. Naturally, if the building is very
reduce our carbon emissions.”
small, or there is no intention to participate in a paid
metering
requirements
will
get
more
program due to restricted opportunities, then lower
Homeowner
metering requirements could be justified.
“I am a semi-detached homeowner in London,
recently my local authority created a phone app
Here are LETI’s suggested general requirements,
that can read my smart meter and gives me a score
which are applicable to all systems regardless of size:
for avoiding using energy during peak periods.
Depending on my score I can get points, which I
Metering should be appropriately sized for the
can redeem for shopping vouchers! I’ve shifted my
building, whereby the least significant figure (LSF) of
washing day to the weekend, and tend to put the
measurement is at the right level of accuracy.
heating on a bit later to help me get more points. I’m
→→ Actual accuracy requirements depend on
considering buying an electric car, and even though
the program participation intended and are
it will raise my electricity bill, apparently, I can set the
generally a percentage of maximum asset
charging time to ‘only overnight’ to gain even more
kW use. Future proofed design would be to
points!”
get 1% overall accuracy, including all errors.
→→ It should be possible to record data on a
minute by minute basis.
→→ Half
hourly
readings
are
a
minimum
requirement for some programs, but is not
useful as it gives you very little information
Climate Emergency Design Guide
Appendix 4
145
about what the systems are doing at any
→→ It also removes the granularity of information
specific moment in time.
that may be gained by knowing what each
→→ Future proofed design would be able to
individual asset is doing.
record second by second metering, as
markets seem to be moving in that direction.
Note: A problem has been identified in industry that
→→ At a minimum minute-by-minute readings
some types of data collection, metering or control
should be recorded.
system are challenging to integrate with due to a
lack of adherence to common standards. These
Regular data collection and storage should occur
systems have no place in an evolving forward looking
automatically, without human intervention, otherwise
development and should be avoided as they can
it will be forgotten about or will become expensive
cause large project costs when future work is being
to record. Currently, flexibility aggregators use data
done - hence adhere to industry standard metering
collection hardware and software solutions to create
practices.
a live data stream from the source, requesting data
as soon as it is recorded.
There
are
often
further
requirements
for
paid
programs (such as accuracy and length of data
Energy data should be securely stored, uneditable,
retention) so please refer to the website and technical
and easily accessible by authorised users or systems.
documentation of the paid program providers for
→→ This implies that a common data transmission
standard and common data format should
be used to ease integration with other
systems or service providers that might be
employed down the line.
→→ Opening up data access or automatic
communication to third parties or networks
can be a cyber security risk. These risks can
be managed, so appropriate steps should
be taken to follow industry guidance on
network and physical security to minimise
potential risks.
→→ Building occupants should be able to access
their own data easily, as this can aid in selfdirected energy efficiency activities.
Flexible assets can be grouped under one meter.
→→ However, this could remove the ability to
use different buildings in different flexibility
programs.
LETI
further information, e.g. National Grid ESO.
Appendix 4
146
A4.5 Reporting
and Auditing
Once an energy flexibility system is in place, the
LETI would only recommend the implementation
auditing methodology can be quite straightforward:
of binding targets for participation after a defined
period of operation, after data is collected and
→→ Participation in formal paid energy flexibility
programs
→→ It can be assumed that a paid program will
be well audited to begin with.
→→ As participants are paid based on their
response, the data should exist digitally.
Therefore, it should be simple to extract data
about the response.
→→ If not taking part in a formal paid program, data
based evidence should be provided to show that
assets have been flexibly shifted to respond to
external requirements, such as carbon saving.
Gains, carbon based, financial or otherwise
should be shown, as adherence to a constrained
connection agreement.
The challenge is defining whether participation is
either below standard or exemplary. It is not thought
that responding only once a year is good enough.
More frequent reporting of performance would be
required.
Using a publicly published rating to rank buildings
against each other would encourage
the use of
demand response systems.
For example, a school has saved ‘X tonnes CO2 per m²
of floor space’ this year, therefore, based on a bellcurve rating system against other schools, it gets a B+
rating. Alternatively, Office Y only utilised their battery
once a month, therefore only get a D rating.
Climate Emergency Design Guide
comparisons can be made.
Appendix 4
147
LETI
Appendix 5
148
A5.1: Proposed
energy reporting
structure
Process
flow
information
diagram
sources
opposite
and
key
showing
outputs
recommended by LETI for energy disclosure.
Key principles for city wide energy disclosure:
1.
The
purpose
is
to
improve
building
benchmarking and to provide transparency
at a city level. It is not intended to allow
diagnosis for individual buildings.
2.
Simplicity
should
be
prioritised
over
resolution of data. The data input by the
applicant has been minimised and mirrors
existing requirements as much as possible.
API and data checking input should be
used to improve data quality.
3.
Voluntarily disclosure from non-referable or
Input by applicant
Input at completion of construction
Reported on whole building by applicant
Possible to input for existing buildings
For non-domestic buildings an annual DEC submission is
sufficient to satisfy the majority of inputs.
Property information
→→ Address
→→ Date of assessment OR Issue date
→→ Completion date
→→ Certificate reference number
→→ Building regulations version (dropdown)
→→ Total floor area OR Total useful floor area
→→ No. of flats
→→ Building description and photo
Building categorisation
→→ DEC Category OR Residential use category
→→ (GRESB Category?)
→→ Possible to select more than one
→→ Gross internal floor area for each use*
→→ Single defined building OR Multiple buildings across
a site (how many?)
Annual displaced CO2 emissions (offset)
→→ From carbon offset fund contributions
existing buildings should be encouraged.
The data should be freely available to the
industry and public.
Input within 14 months of completion
Annual updates by applicant for minimum of 5 years
Energy consumption
→→ Over bespoke date range
→→ Identify primary heating source
→→ Metered electricity consumption (kWh)
→→ Metered gas consumption** (m3/kWh/cf)
→→
→→
Other fuel consumption** (m3/kWh/cf)
Metered heat consumption for building (kWh)
(required for district heating, optional for other
buildings. Dropdown menu for heat network
provider to give carbon factor)
Energy generation
→→ Metered export generation over date range
chosen, split between PV and other
→→ Metered electricity generation (kWh)
Climate Emergency Design Guide
Appendix 5
149
From external source
Output by platform
Carbon content of fuel (kgCO2e/kWh)
→→ Conversion factors for greenhouse gases
→→ Options for different value sets to be
substituted in by viewer (not applicant) -
Publicly disclosed for each building
Includes summary building information including area
Total energy consumption (kWh/m2)
→→ Broken down by building and fuel type
default values set by GLA
Energy conversion factors
E.g. Volume to kWh
→→
Total annual CO2e emissions from building (kgCO2e/m2)
→→ Broken down by building and fuel type
Calorific values
Total net CO2e emissions from building (kgCO2e/m2)
→→ Shown against offset contribution and emissions
displaced at planning
Cost of energy (£/kWh)
→→ Ofgem reported figures
Estimated energy cost per residential unit (£pa)
Calculated by platform
Annual consumption (kWh)
→→ Electricity
→→ Gas
→→
Total annual CO2e emissions (kgCO2e)
→→ Imported electricity indirect emissions
→→ Combusted fuel direct emissions e.g. gas burned
on site
→→ District heating system indirect emissions
→→ Renewable electricity generated on site (PV)
→→ Each per building for larger sites
Other fuel broken down by fuel type
Annual electricity generation (kWh)
→→ Broken down between PV and other
Key
Information
available
from
Energy
Performance Certificate for all buildings
Information available from Display Energy
Certificate (DEC) for buildings other than
dwellings
*
Information is only available in DEC full
technical table report supplement. Additional
requirement for mixed-use schemes
**
Fuel and heat consumption are combined
into one output on DEC
LETI
Appendix 6
150
A6.1: Definitions
Air tightness: measures the infiltration of outdoor
Carbon factor:
air into the building, or in other words how ‘leaky’
to electricity that is consumed by buildings, to
or ‘draughty’ the building is. A low energy building
understand that carbon emissions associated with
requires high levels of airtightness. Airtightness is
the electricity use. The carbon factor of the UK
measured in m /h.m at a pressure of 50Pa (the pressure
grid changes throughout the day and the seasons
of the airtightness test). It can also be measured in air
depending on how much renewable energy is being
changes per hour through the external envelope. In
generated.
3
2
either case, the lower the value the better.
It is the factor that is applied
Carbon sequestration: A natural or artificial process
Ambient loop: a heat sharing network at a low
by which carbon dioxide is removed from the
temperature that can be used to share heat between
atmosphere and held in solid or liquid form, e.g.
floors of buildings, or between different buildings. An
reforestation or, in the built environment through using
ambient loop can be used to and make use of waste
timber.
heat between buildings. E.g. an office building’s air
conditioning system can reject heat an ambient loop,
(rather than atmosphere), this heat can then be used
by a neighbouring residential development.
Combustion process: The chemical process of burning
via a substance (fuel) reacting rapidly with oxygen
Archetype: In the context of this document, one of
four building typologies used as a means of modelling
certain design criteria and targets to determine
specific recommendations.
and giving off heat.
Community
and/or electricity derived from biomass (agricultural,
forest, urban or industrial residues as opposed to fossil
fuel).
renewables: a means of providing
electricity via installations of renewable (e.g. solar
panels,
Biomass boiler: A form of direct combustion, heating
Biofuel:
Circular economy: See page 25.
wind turbines) that are owned by, or
have significant benefits for, residents and local
organizations.
Cradle-to-cradle: Goes beyond ‘cradle to grave’ and
conforms more to the model of the circular economy.
Is
a
fuel
that
is
produced
through
contemporary processes from biomass, not fossil fuel.
In a cradle to cradle model products would be
designed in a way so that at the end of their initial
life they can be readily reused, or recycled, and
Biogenic carbon: Emissions are those that originate
therefore avoid landfill altogether. (source: www.
from biological sources such as plants, trees, and soil.
circularecology.com)
Bottom-up modelling: In the context of this document,
Cradle-to-gate: A boundary condition associated
using archetypes with varying key design parameters
with embodied carbon, carbon footprint and LCA
to determine realistically achievable EUIs and an
studies. It considers all activities starting with the
‘optimised’ design. Refer to page 47.
extraction of materials from the earth (the cradle),
their
Climate Emergency Design Guide
transportation,
refining,
processing
and
Appendix 6
151
fabrication activities until the material or product is
ready to leave the factory gate. See also embodied
energy. (source: www.circularecology.com)
Cradle-to-grave: A boundary condition associated
with embodied carbon, carbon footprint and LCA
studies. It includes the cradle to site results but also
includes the GHG emissions associated with the in
use of the material or product (maintenance) and the
end of life (disposal, reuse, recycling). (source: www.
circularecology.com).
Dead leg: The length of pipe to the outlet in a hot
water system. When the outlet is not in use the hot
water in this pipe loses its heat so when next used
there is a time delay before fully hot water is again
available at the outlet. This represents an inefficiency
of the heat system.
Demand response: The ability of a system to reduce
or increase energy consumption for a period of time
in response to an external driver (e.g. energy price
change, electricity grid availability). Refer to this
Embodied carbon (EC): See page 24.
Embodied energy (EE): See page 24.
Energy budget: A specific target for Energy Use
Intensity (EUI) that LETI believe developments must
not exceed in order to achieve net zero carbon,
as demonstrated through archetypes. See also
top-down modelling.
Energy
flexibility
assessment:
The
concept
of
recording the total kW of energy available that can
be controlled and how long the consumption can be
reduced, or energy stored for on a per building basis.
See also this document Chapter 4.
Energy use intensity (EUI): See page 24.
Environmental Product Declaration (EPD): See page
56.
Feedback loop: In the context of this document, this
describes communicating the disparity between
design and operation. The lack of a feedback loop is
document, Chapter 4.
the primary cause of the performance gap.
District heating: Also known as a heat network, it is a
Firm Frequency Response (FFR): Allows a provider
system for distributing heat generated in a centralized
location through a system of insulated pipes for
residential and commercial heating requirements
to provide a service whereby they may reduce the
electricity consumption of a building or increase
generation of electricity, when instructed by National
such as space heating and water heating.
Grid.
Dynamic carbon factor: Variation in carbon emissions
Form factor: a design parameter defined, for the
from the grid at different times of the day and year.
Electric vehicle turn-down: Charging electric vehicles
only when needed and allowing the electricity
supplier to stop charging the electric vehicles during
peak electricity grid constraints. See this document
p.94.
LETI
purposes of LETI and operational energy, as the
efficiency of the shape of a building.
Fossil fuel: A natural fuel such as petroleum, coal or
gas, formed in the geological past from the remains of
living organisms. The burning of fossil fuels by humans
is the largest source of emissions of carbon dioxide,
Appendix 6
152
which is one of the greenhouse gases that allows
typical air conditioning systems remove heat from the
radiative forcing and contributes to global warming.
building, transferring it to the air outside the building,
Fuel poverty: A household is said to be in fuel poverty
when its members cannot afford to keep adequately
warm at a reasonable cost, given their income.
Geothermal: Heat derived within the sub-surface of
the earth. Water and/or steam carry the geothermal
energy to the Earth’s surface. Depending on its
characteristics, geothermal energy can be used for
heating and cooling purposes or be harnessed to
generate clean electricity.
Glazing ratio: The proportion of glazing to opaque
surface in a wall. Also called window-to-wall ratio, it
is a key variable in façade design affecting energy
this means that while air conditioning systems cooling
the inside of the building they make the air outside
the building hotter.
Heat pump: Heat pumps transfer heat from a lower
temperature source to one of a higher temperature.
This is the opposite of the natural flow of heat. Heat
pumps can be used to provide space heating,
cooling and hot water. A refrigerant fluid is run through
the lower temperature source (ambient air, ground,
water, etc.). The fluid ‘absorbs’ heat and boils, even
at temperatures below 0°C (although the coefficient
of
performance
(COP)
decreases
with
lower
temperature). The resulting gas is then compressed,
performance in buildings.
which further increases its temperature. The gas is
Ground granulated blast-furnace slag (GGBS): A
releasing its latent heat. The process then repeats.
cement substitute in concrete applications.
Ground source heat pump (GSHP): A form of
renewable heating or cooling system that transfers
heat to or from the ground.
G-value: Sometimes also called a Solar Factor or
Total Solar Energy Transmittance, it is the coefficient
commonly used in Europe to measure the solar energy
transmittance of windows.
Heat autonomy: Term used to describe a dwelling
or other building that has self-sufficiency for heat
and requires no heating system. This tends to mean
sufficiently good building thermal performance to
permit incidental room heat gains or similar sources
to be recovered and upgraded to meet the residual
heat demands.
Heat island effect: An urban area or metropolitan
area that is significantly warmer than its surrounding
rural areas due to human activities. This can be
caused be air conditioning systems, for example
Climate Emergency Design Guide
passed into heat exchanger coils, where it condenses,
(Adapted
from
https://www.designingbuildings.
co.uk/wiki/Heat_pump).
Heat sharing network: a network at a low temperature
that can be used to share heat between floors of
buildings, or between different buildings. E.g. an
office building’s air conditioning system can reject
heat an ambient loop, (rather than atmosphere), this
heat can then be used by a neighbouring residential
development.
Incidental room heat gains: Heat gains to a room
other than from the heating system. This could include
heat gains from people, lighting, appliances and
energy consuming equipment. It can also be from
solar heat gain through glazing.
LETI Heat Decision Tree: Highlights the broad range of
issues that the heating system selection must address,
including; carbon emissions, avoiding higher energy
bills, air quality issues, and countering future urban
‘heat island’ increases.. See this document p.80.
Appendix 6
153
Life cycle assessment: See page 56.
systems used to deliver the heat. Sometimes called
Mechanical ventilation with heat recovery (MVHR):
MVHR, heat recovery ventilation (HRV) or ventilation
heat recovery (VHR) uses a heat exchanger to recover
‘point of use’ heat demands. For space heating this
would include improving the building envelope and
reducing the infiltration of outdoor air.
heat from extract air that would otherwise be rejected
Peak demand: Refers to the times of day when our
to the outside and uses this heat to pre-heat the ‘fresh’
electricity consumption is at its highest which, in the
supply
UK, occurs between 5-30pm to 6pm each weekday
air.
(https://www.designingbuildings.co.uk/
wiki/Thermal_bridging_in_buildings) As a result, MVHR
is more energy efficient than natural ventilation, whilst
also providing air quality and acoustics benefits.
Microgrid: A key component contributing to demand
response and energy storage. A small semi-isolated
energy network that allows the development to
operate as an ‘energy island’, essentially cutting itself
off from national energy networks if needs arise. See
this document p.96.
evening.
Performance gap: This term refers to the discrepancy
between
energy
predictions
at
design
stage,
compared to in-use energy consumption of buildings.
Post-occupancy evaluation (POE): Post-occupancy
evaluation is the process of obtaining feedback on a
building’s performance in use after it has been built
and occupied. By accurately measuring factors such
as building use, energy consumption, maintenance
Net zero operational carbon: A new building that
costs and user satisfaction, POE allows for a process
achieves a level of energy performance in-use in
of continuous improvement in the construction
line with our national climate change targets that
industry.(Source:
does not burn fossil fuels and that is 100% powered by
media/gathercontent/post-occupancy-evaluation/
renewable energy.
additional-documents/ribapoebpeprimerpdf.pdf)
Offsetting: Offsetting is the process of compensating
Primary energy: See page 25.
for the remaining carbon emissions balance by
contributing, usually financially, towards solutions to
reduce emissions elsewhere. Typically, this is put in
practice by establishing carbon offset funds which
then invest in renewable energy and other carbon
reduction measures. See Appendix 10 of the LETI
Embodied Carbon Primer for more information.
Open source data: Data that is publicly available,
that is released in a specific way to allow the public
to access it without having to pay fees or be unfairly
restricted in its use.
LETI
Renewable energy: Renewable energy technologies
use natural energy sources to generate electricity
and/or heating/cooling. Sources include solar, wind,
wave, marine, hydro, etc..
Soft Landings Framework: The term soft landings refers
to a strategy designed to make an easy transition
from the construction to occupation phases of a
project with the overriding aim of realising optimal
the performance gap between design intent and
operational outcomes that can emerge at any stage
Passive heat demand reduction: Reduction in heat
before
Regulated energy: See page 24.
operational performance. It’s all about narrowing
Operational carbon (kgCO2e): See page 24.
demands
https://www.architecture.com/-/
consideration
of
the
(active)
in a construction project. (source: www.thenbs.com)
Appendix 7
154
Solar thermal: Is a renewable form of energy and a
and processing of materials and the energy and
technology for harnessing solar energy to generate
water consumption in the production, assembly,
thermal energy. Devices are often roof mounted to
and construction of the building. This is distinct from
absorb the sun’s heat and use it to heat up water,
“in-use” and “end of life” stages.
stored in a cylinder.
Thermal bridge: Heat makes its way from the heated
space towards the outside. In doing so, it follows the
path of least resistance. A thermal bridge is a localised
area of the building envelope where the heat flow
is different (usually increased) in comparison with
adjacent areas (if there is a difference in temperature
between the inside and the outside). (https://www.
passipedia.org/basics/building _ physics _ - _ basics/
thermal _ b ridges/thermal_bridge_definition).
Thermal mass: A property of the a material in a
building which enables it to store heat, providing
“inertia” against temperature fluctuations. It will
absorb thermal energy when the surroundings are
higher in temperature than the mass, and give thermal
Urban heat island: see ‘heat island effect’
U-Value: the rate of transfer of heat through a structure
(which can be a single material or a composite),
divided by the difference in temperature across that
structure. The units of measurement are W/m²K.
Vehicle to grid: This reverse charging EV technology
allows the battery of the EV to be used to supply the
building. See this document p.49.
Waste
water
heat
recovery
system:
Works
by
extracting the heat from the water a shower or bath
sends down the drain. This heat is used to warm the
incoming mains water, reducing the energy required
to heat the water up.
energy back when the surroundings are cooler.
Whole life carbon (WLC): See page 25.
Thermal storage: Thermal energy storage is achieved
Zero carbon balance: A building that achieves a
with widely differing technologies. It allows excess
thermal energy to be stored and used hours, days,
months later. In the context of this document, it is
usually refers to hot water stores in buildings.
Top-down modelling: In the context of this document,
the setting of EUI “ceilings” for building archetypes
based on forecasts for available renewable energy
generation in the UK to the average total floor area.
Refer to this document to p.47.
Upfront embodied carbon: See page 24.
Unregulated energy: See page 24.
Upfront emissions: The embodied carbon associated
with building construction, including the extraction
Climate Emergency Design Guide
zero carbon balance is 100% powered by renewable
energy, achieves a level of energy performance
in-use in line with our national climate change targets
and does not burn fossil fuel.
Appendix 7
155
A7.1: Abbreviations
A/C
Air Conditioning
GWP
AHU
Air Handling Unit
APF
Assured Performance Framework
HVAC
Heating , Ventilation and Air Conditioning
ASHP
Air-source heat-pump
IEA
International Energy Agency
BBP
Better Buildings Partnership
IoT
Internet of Things
BIM
Building Information Modelling
BRE
Building Research Establishment
IPCC
Intergovernmental Panel on Climate
Change
BREEAM
Building Research Establishment Environmental Assessment Method
Global Warming Potential
LBSM
London Building Stock Mode
LCA
Life Cycle Assessment
BUS
Building Use Studies
LETI
London Energy Transformation Initiative
CCC
Committee on Climate Change
MEV
Mechanical Extract Ventilation
CCS
Carbon Capture and Storage
MEP
Mechanical, Electrical and Public health
CHP
Combined heat and power unit (usually gas-fired)
MVHR
Mechanical Ventilation with Heat Recovery
CIBSE
Chartered Institution of Building Services
Engineers
NABERS
National Australian Built Environment
Rating System
CLT
NBS
National Building Specification
NRM
New Rules of Measurements
Pulverised Fuel Ash
Cross Laminated Timber
CO2Carbon Dioxide
COP
Coefficient of performance
PFA
DEC
Display Energy Certificate
PHPassivhaus
DfMA
Design for Manufacture and Assembly
PHPP
Passivhaus Planning Package
DHW
Domestic hot water
POE
Post Occupancy Evaluation
DNO
Distribution Network Operator
RIBA
Royal Institute of British Architects
DX
Refrigerant piped between split units
(often reverse-cycle)
RICS
Royal Institute of Chartered Surveyors
SCoP
Seasonal Coefficient of Performance
EAHP Exhaust-air-source heat-pump
SEER
Seasonal Energy Efficiency Rating
EAM
Environmental Assessment Method
SFP
Specific Fan Power
EC
Embodied Carbon
UHI
Urban Heat Island
EoL
End of Life
UKGBC
United Kingdom Green Building Council
FSC
Forest Stewardship Council
VRV
Variable Refrigerant Volume
GGBS
Ground Granulated Blast-furnace Slag
WGBC
World Green Building Council
GHG
Greenhouse Gases
WSHP
Water source heat pump
GIA
Gross Internal Area
WLC
Whole life carbon
GLA
Greater London Authority
ZCZero carbon
LETI
Appendix 8
156
A8.1: Acknowledgements
Editorial Team
Lead Editor and Co-ordinator - Clara Bagenal George - Elementa Consulting
Design Editor - Clare Murray - Levitt Bernstein
James Woodall - Allies and Morrison
Debby Ray - Woods Bagot
Chapter 1 - Operational Energy
Workstream Lead - John Palmer- Passivhaus Trust and
James Woodall - Allies and Morrison
Thomas Lefevre - Etude
Tom Gwilliam - Greengage
Jennifer Elias - Cundall
Rachael Collins - AECOM
Jake Attwood-Harris - Hawkins Brown
Amber Fahey - BDP
Charlotte Booth - Hodkinson Consultancy
Georgios Askounis - KLH Sustainability
Isabelle Smith - Atkins
Sabrina Friedl - Allies and Morrison
Stephen Barrett - Lower Carbon
Dr Alina Congreve - Independent research
Helen Newman - TFT Consultants
Louisa Bowles - Hawkins Brown
Wyn Gilley - APLB/ACAN
Joe Giddings - Variant Office/ACAN
Seb Lomas - Hopkins/ACAN
Jack William Taylor - ACAN
Ed Cremin - Etude
Chapter 3 - Future of Heat
Dr Alina Congreve - Independent researcher
Workstream Leads - Chris Twinn - Twinn Sustainability
Nazli Dabidian - Mecserve
Innovation and Nuno Correia - XCO2
Susie Diamond - Inkling
Samantha Crichton - Sustainable Energy Association
Bertie Dixon - Inside Outside
Debby Ray - Woods Bagot
Federico Seguro - TB+A
Daniel Raymond - Expedition
Dan Wright - Loughborough University
Peter Mortimer - Showersave
Isabelle Smith - Atkins
Charlotte Booth - Hodkinson Consultancy
Hugh Dugdale - Elementa Consulting
Chapter 2 - Embodied Carbon
Workstream Leads - Mirko Farnetani - Hilson Moran
and Tim Pryce ( Jan-May 19)
Ben Hopkins - Bennetts Associates
Colin Beattie - John Robertson Architects
Duncan Cox - Thornton Tomasetti
Erica Russell - University of Surrey
Julie Godefroy - Julie Godefroy Sustainability/CIBSE
Kat Scott - dRMM
Louise Hamot - Elementa Consulting
Raheela Khan-Fitzgerald - Hawkins Brown
Simon Mitchell - SSE
Alan Morton - en10ergy
Miles Attenborough - AECOM
Federico Seguro - TB+A
Monica Donaldson-Balan - Mott MacDonald
Idil Alcinkaya - XCO2
Eleni Pyloudi - XCO2
Appendix 8
157
Chapter 4 - Demand Response and Energy Storage
Workstream Lead - Fraser Tooth
Nazli Dabidian - Mecserve
Simon Mitchell - SSE
Anthony Thornton
Quinten.Babcock - TfL
Eric Roberts - IESVE
Weiwen Low - Mott MacDonald
Alex Johnstone - Haworth Tompkins
Reviewers
Chris Twinn - Twinn sustainability Innovation
Joe Jack Williams - FCBS
Sam Botterill - Demand Side Response and
Titi Olasode - Hawkins Brown
Rowan Riley - Haworth Tompkins
Gabriella Seminara - ECDA
Carolina Caneva - PRP
Martha Baulcombe - FCBS
Alex Johnstone - Haworth Tompkins
James Parker - Clarion Housing
Michelle Sanchez - PDP London
Charlotte Millbank - Levitt Bernstein
Zoe Watson - Levitt Bernstein
Patrick Matheson - Elementa Consulting
Grace Van Der Zwart - Elementa Consulting
Amber James - Elementa Consulting
Rebecca Goodson - BDP
Blockchain
Devrim Celal - Upside Energy
Eric Bakken - ENEL
Chapter 5 - Data Disclosure
Workstream Lead - Will South - Etude
Andy Stanton- Atkins
Adam Mactavish - Currie & Brown
Robert Cohen - Verco
Quinten Babcock - TfL
Jake Atwood Harrison - Hawkins Brown
James Woodall - Allies and Morrison
Proofreading team
Tim Mitchell - Kilma Therm
Lilija Oblecova
Deborah Elliott - Create Consulting Engineers Ltd
Jennifer Juritz - David Morley Architects
Sean Mills - Build Energy
Durgesh Chadee - MZA consult
Rossella Perniola - Scotch Partners
Alexia Laird - Landsec
Sydney Charles - en10ergy
Anna Woodeson - LTS
James Parker - Clarion Housing
Reviewers
Jatinder Padda - Raining Words
Bill Bordass
Tim Pryce
Zack Gill - SOAP Retrofit
Lucy Townsend - BDP
Sally Godber - WARM
Megan VanDessel - Meinhardt
Judit Kimpian
Peter Courtenay - Bouygues
Georgie Rose
Graphics Team
Graphics team coordinator - Helen Hough - Bryden
Wood
James Watts - LTS
Louise Claeys - CZWG Architects
Karly Wilson-Ros - CZWG Architects
Elisabeth George
Tim Hume - Elementa Consulting
Alex Pepper - Elementa Consulting
Martin Bull - Elementa Consulting
Nathan Millar - Elementa Consulting
Tom Randall - Verco
Colette Connolly - Elementa Consulting
Sydney Charles - en10ergy
Appendix 8
158
This is a climate emergency
We are in a climate emergency,
and urgently need to reduce
carbon emissions. Here in the UK,
49% of annual carbon emissions are
attributable to buildings. Over the
next 40 years, the world is expected
to build 230 billion square metres
of new construction – adding the
equivalent of Paris to the planet
every single week – so we must
act now to meet the challenge of
building net zero developments.
The London Energy Transformation
Initiative have developed this
Climate Emergency Design Guide
to provide practical solutions for
the built environment - setting out a
definitive journey, beyond climate
emergency declarations, into a net
zero carbon future.
www.leti.london
@LETI_London
admin@leti.london
Jan 2020 edition